Luminosity Functions of Planetary Nebulae & Globular Clusters. By Azmain Nisak ASTR 8400

Size: px
Start display at page:

Download "Luminosity Functions of Planetary Nebulae & Globular Clusters. By Azmain Nisak ASTR 8400"

Transcription

1 Luminosity Functions of Planetary Nebulae & Globular Clusters By Azmain Nisak ASTR 8400

2 Calculating Distance! m = apparent magnitude! M = absolute magnitude! r = distance in pc

3 GLOBULAR CLUSTERS AS DISTANCE INDICATORS

4 GCLF: Procedure! Collect apparent magnitudes of as many globular clusters as you can.! Plot these in a histogram. This magnitude distribution is called the Globular Cluster Luminosity Function (GCLF).! Fit this function to some standard law! The apparent magnitude corresponding to the peak of this distribution is called the Turn-Over Magnitude (TOM)! It is known that the absolute TOM is a constant (M V,TO -7.5)! Use the distance modulus equation to solve for distance

5 GCLF: Example

6 Why GCLF! Comparison of TOMs for galaxies at the same distance (i.e. same galaxy cluster) reveals a scatter of 0.15 without correcting for any error! Taking into account errors, internal dispersion of TOMs is <0.1, which makes globular clusters a useful standard candle! A constant absolute TOM suggests a universal characteristic mass in the globular cluster mass distributions in all galaxies. The origin of this is still unclear! Distance over which GCLF can be used is constrained by limiting magnitude required to reach the peak of the GCLF Using Hubble Space Telescope (HST) or 10-m telescope, reaching V ~ 28, the method can be applied up to 120 Mpc (including Coma galaxy cluster)! Globular clusters are brighter than other standard candles (except for supernovae), do not vary (i.e. no repeated observations), and are usually measured at large radii or in the halo of (mostly elliptical) galaxies where reddening is not a concern.

7 Fitting the GCLF! Which standard law is used? Gaussian t5 function

8 Gaussian vs. t5! Left: Milky Way GCLF fitted with a Gaussian (solid line) and t5 function (dashed line) in magnitude units! Right: Milky Way GCLF fitted with a Gaussian (solid line) and t5 function (dashed line) in luminosity units! t5 fits better overall but both are sufficient to getting the TOM

9 Example Calculation! Kavelaars et al. (1997) confirmed the TOM for NGC 4697, a calibrator galaxy of the Virgo cluster. They calculated m R TO = 22.9, m-m = 31.0, and V-R = 0.6. What was the M V TO they calculated?! M V TO = -7.5

10 Sources of Error! Must correct for luminosity function of background galaxies (these tend to mimic a fainter TOM! Must account for photon noise as a function of galactocentric distance, which can affect how incomplete your sample of GC is! Must apply correction for reddening. The correction you make depends on what reddening map you use! In some images, the clusters may be slightly extended. Therefore, a proper aperture correction must be applied.! The function you use to fit your GCLF can have an effect on your computed TOM. The most commonly used functions are Gaussian and t5! What you consider the absolute TOM depends on what globular cluster system (GCS) you are calibrating with. This can introduce some error! Your GCLF may be impacted by galaxy type due to mean metallicity of globular clusters differing in early- and late-type galaxies! The net effect of these errors sum up to several tenths of a magnitude]

11 Two Main Methods! Classical Way Uses all globular clusters in a galaxy Uses GCLF as a secondary distance indicator, calibrating to elliptical galaxies in the Virgo cluster, whose TOMs are determined from primary distance indicators (like Cepheids)! Alternate Way Uses metal-poor globular clusters only Uses GCLF as an independent distance indicator, and uses the Milky Way GCLF for calibration. The Milky Way GCLF is determined by calculating distances to globular clusters in the Milky Way using the known apparent magnitudes of their horizontal branches and a relation between the absolute magnitude of the horizontal branch and the metallicity. (see Gratton et al for more details)

12 The Classical Way! Advantages Using all globular clusters in a galaxy as opposed to a limited sub-population avoids problems with small number statistics. Using Virgo GCLFs instead of the Milky Way GCLF is useful because these are giant elliptical galaxies rich in globular clusters, are well-sampled, and do not suffer from small number statistics.! Disadvantages Giant ellipticals are known to have globular cluster subpopulations with different ages and metallicities. Therefore, using all globular clusters in the galaxy causes one to sample a mix of TOMs. This causes the GCLF to become broader and its TOM to be displaced. Errors of several tenths of a magnitude are introduced. Using GCLF as a secondary distance indicator is problematic because errors from the primary distance indicators used for calibration carry through.

13 The Alternate Way! Advantages Takes into account subpopulations in Globular Cluster Systems (GCS).! We use metal-poor globular clusters (GC) because they appear to have a true universal origin, their properties are relatively independent of galaxy type, environment, size, and metallicity, they appear to be halo objects weakly affected by those GCs closer to the galactic center or those on radial orbits, and because they will form a much more homogenous population than the total GCS. The Milky Way GCLS is a good calibrator because its GCLF is independent of other distance indicators (like Cepheids).! Disadvantages Choosing metal-poor globular clusters requires more complicated and timeconsuming observations Perfect separation is not possible and there will probably always be some contamination of metal-rich clusters. The sample size will be cut in half, inducing errors > 0.1 on the GCS TOM.

14 Recent Result! Rejkuba, M. (2012) reveals Left: Milky Way GCLF using all GCS (Black) vs. metal-poor GCS (Blue) Right: Dependence of TOM on metallicity and filter for Milky Way GCS

15 PLANETARY NEBULAE AS DISTANCE INDICATORS

16 PNLF: Procedure! Identify as many planetary nebulae in the galaxy of interest as possible, making use of their bright [O III] λ5007 emission line.! Make a histogram of the apparent magnitudes of these objects at this wavelength. This distribution of magnitudes is called the Planetary Nebula Luminosity Function (PNLF)! Fitting the distribution to a standard law, identify the magnitude of the brightest planetary nebula in the galaxy! Calibrating to the known absolute magnitude of the brightest planetary nebula, use the distance modulus equation to compute the distance to the galaxy.

17 Why PNLF! One of the most reliable ways of getting distances to elliptical galaxies out to about 20 Mpc. The limiting distance for this method may be 50 Mpc for an 8-m telescope with excellent detector and seeing! Good agreement with other distance indicators Disagreements between PNLF and other reliable methods (i.e. Cepheids) are smaller than 8%. Thus, systematic errors due to extinction, age, metallicity, or application of the method are not accumulating beyond the 8% level. In fact, if errors from Cepheid distances are taken into account, the PNLF errors must be smaller than ~ 5%.! PNLF is insensitive to population age and metallicity! PNLF is invariant with Galaxy color, metallicity, and Hubble type Well defined PNLFs currently (1992) exist for 17 giant spiral, elliptical, and irregular galaxies. In none of these objects is there any evidence for a change in the shape of the PNLF cutoff! M = 4.47 ± 0.05

18

19 Fitting the PNLF! Truncated exponential is most popular:

20 Problems and Sources of Error! Contamination H II Regions: Star formation is not an issue in most elliptical and lenticular galaxies, but in late-type systems, the H II regions around O and B stars will far outnumber the PNe. Fortunately, most H II regions are resolvable under good seeing conditions, and their exciting stars may be visible on deep continuum images. Supernova Remnants: Unresolved high-excitation supernova remnants can masquerade as planetary nebulae, especially in galaxies that have a cold, high density interstellar medium. Because compact supernova remnants are rare, their effect on the PNLF is minimal. Lyα Galaxies: At z = 3.12, Lyα is redshifted to 5007 A. Unresolved and marginally resolved high-redshift galaxies with extremely strong Lyα emission can mimic planetary nebulae. The surface density of these star-bursting objects is relatively low so PN surveys in galaxies are not strongly affected by this contaminant.

21 Problems (cont.)! Correcting for interstellar extinction Must correct for extinction in Milky Way. Can use reddening maps. Internal extinction in host galaxy (only a problem in late-type spiral and irregular galaxies). Estimated to be approximately equal to or greater than 0.5 mag.! Considerations for Spirals Potential confusion between PN and H II regions Spiral arms contain dust lanes that could reduce observed luminosities A young population of stars must exist within spiral arms

22 Recent Result! Mendez R. (1999) computes values for PNLF of M81 using M31 (770kpc) as calibration. Obtained m(5007) = 23.64, m-m=27.78, extinction correction of 0.36, and M =

23 References! Ciardullo, R., The Planetary Nebula Luminosity Function, ESO Intl. Workshop on "Planetary Nebulae beyond the Milky Way" (2004).! Forbes, D., Globular Cluster Luminosity Functions and the Hubble Constant from WFPC2 Imaging: The Giant Elliptical NGC4365, Astron. J. 112 (3), (1996).! Jacoby et al., The Planetary-Nebula Luminosity Function, Publ. Astron. Soc. Pac. 104: (1992).! Jacoby G., Verifying the Planetary Nebula Luminosity Function Method, Cambridge University Press (1997).! Kavelaars, J.J. & Gladman, Brett., Probing the Shape of the Globular Cluster Luminosity Function, Proceedings of CFHT Users Meeting (1998).

24 References (cont.)! Kissler-Patig, M., Extragalactic Globular Cluster Systems: A New Perspective on Galaxy Formation and Evolution, Reviews in Modern Astronomy 13, (2000).! Mendez, R., Distances from the Planetary Nebulae Luminosity Function, Astrophys. Space Sci. 237, (1999).! Rejkuba, M., Globular cluster luminosity function as distance indicator, Astrophys. Space Sci. 341, (2012).! Richtler, T., The Globular Cluster Luminosity Function: New Progress in Understanding an Old Distance Indicator, Lect. Notes Phys. 635, (2003).!

Practice Problem!! Assuming a uniform protogalactic (H and He only) cloud with a virial temperature of 10 6 K and a density of 0.

Practice Problem!! Assuming a uniform protogalactic (H and He only) cloud with a virial temperature of 10 6 K and a density of 0. Practice Problem Assuming a uniform protogalactic (H and He only) cloud with a virial temperature of 10 6 K and a density of 0.05 cm -3 (a) estimate the minimum mass that could collapse, (b) what is the

More information

The cosmic distance scale

The cosmic distance scale The cosmic distance scale Distance information is often crucial to understand the physics of astrophysical objects. This requires knowing the basic properties of such an object, like its size, its environment,

More information

Planetary Nebulae beyond the Milky Way historical overview

Planetary Nebulae beyond the Milky Way historical overview Planetary Nebulae beyond the Milky Way historical overview M. J. Barlow Dept. of Physics & Astronomy University College London Outline (a) Surveys for planetary nebulae in other galaxies, PN luminosity

More information

View of the Galaxy from within. Lecture 12: Galaxies. Comparison to an external disk galaxy. Where do we lie in our Galaxy?

View of the Galaxy from within. Lecture 12: Galaxies. Comparison to an external disk galaxy. Where do we lie in our Galaxy? Lecture 12: Galaxies View of the Galaxy from within The Milky Way galaxy Rotation curves and dark matter External galaxies and the Hubble classification scheme Plotting the sky brightness in galactic coordinates,

More information

Distance Measuring Techniques and The Milky Way Galaxy

Distance Measuring Techniques and The Milky Way Galaxy Distance Measuring Techniques and The Milky Way Galaxy Measuring distances to stars is one of the biggest challenges in Astronomy. If we had some standard candle, some star with a known luminosity, then

More information

Galaxies. Lecture Topics. Lecture 23. Discovering Galaxies. Galaxy properties. Local Group. History Cepheid variable stars. Classifying galaxies

Galaxies. Lecture Topics. Lecture 23. Discovering Galaxies. Galaxy properties. Local Group. History Cepheid variable stars. Classifying galaxies Galaxies Lecture 23 APOD: NGC 3628 (The Hamburger Galaxy) 1 Lecture Topics Discovering Galaxies History Cepheid variable stars Galaxy properties Classifying galaxies Local Group 2 23-1 Discovering Galaxies

More information

Techniques for measuring astronomical distances generally come in two variates, absolute and relative.

Techniques for measuring astronomical distances generally come in two variates, absolute and relative. Chapter 6 Distances 6.1 Preliminaries Techniques for measuring astronomical distances generally come in two variates, absolute and relative. Absolute distance measurements involve objects possibly unique

More information

Part two of a year-long introduction to astrophysics:

Part two of a year-long introduction to astrophysics: ASTR 3830 Astrophysics 2 - Galactic and Extragalactic Phil Armitage office: JILA tower A909 email: pja@jilau1.colorado.edu Spitzer Space telescope image of M81 Part two of a year-long introduction to astrophysics:

More information

Mapping the oxygen abundance in an elliptical galaxy (NGC 5128)

Mapping the oxygen abundance in an elliptical galaxy (NGC 5128) Mapping the oxygen abundance in an elliptical galaxy (NGC 5128) Jeremy R. Walsh, ESO Collaborators: George H. Jacoby, GMT Observatory, Carnegie; Reynier Peletier, Kapteyn Lab., Groningen; Nicholas A. Walton,

More information

Lecture 32: The Expanding Universe Readings: Sections 26-5 and 28-2

Lecture 32: The Expanding Universe Readings: Sections 26-5 and 28-2 Lecture 32: The Expanding Universe Readings: Sections 26-5 and 28-2 Key Ideas Measuring the Distances to Galaxies and Determining the Scale of the Universe Distance Methods: Trigonometric Parallaxes Spectroscopic

More information

Galaxies. The majority of known galaxies fall into one of three major classes: spirals (78 %), ellipticals (18 %) and irregulars (4 %).

Galaxies. The majority of known galaxies fall into one of three major classes: spirals (78 %), ellipticals (18 %) and irregulars (4 %). Galaxies Collection of stars, gas and dust bound together by their common gravitational pull. Galaxies range from 10,000 to 200,000 light-years in size. 1781 Charles Messier 1923 Edwin Hubble The distribution

More information

Hubble s Law. Tully-Fisher relation. The redshift. λ λ0. Are there other ways to estimate distances? Yes.

Hubble s Law. Tully-Fisher relation. The redshift. λ λ0. Are there other ways to estimate distances? Yes. Distances to galaxies Cepheids used by Hubble, 1924 to show that spiral nebulae like M31 were further from the Sun than any part of the Milky Way, therefore galaxies in their own right. Review of Cepheids

More information

24.1 Hubble s Galaxy Classification

24.1 Hubble s Galaxy Classification Chapter 24 Galaxies Units of Chapter 24 24.1 Hubble s Galaxy Classification 24.2 The Distribution of Galaxies in Space 24.3 Hubble s Law 24.4 XXActive Galactic Nuclei XXRelativistic Redshifts and Look-Back

More information

Measuring the Hubble Constant through Cepheid Distances

Measuring the Hubble Constant through Cepheid Distances Measuring the Hubble Constant through Cepheid Distances Final Results from the Hubble Space Telescope Key Project to Measure the Hubble Constant Freedman, Madore, Gibson, et al., Astrophysical Journal

More information

Our View of the Milky Way. 23. The Milky Way Galaxy

Our View of the Milky Way. 23. The Milky Way Galaxy 23. The Milky Way Galaxy The Sun s location in the Milky Way galaxy Nonvisible Milky Way galaxy observations The Milky Way has spiral arms Dark matter in the Milky Way galaxy Density waves produce spiral

More information

Chapter 14 The Milky Way Galaxy

Chapter 14 The Milky Way Galaxy Chapter 14 The Milky Way Galaxy Spiral Galaxy M81 - similar to our Milky Way Galaxy Our Parent Galaxy A galaxy is a giant collection of stellar and interstellar matter held together by gravity Billions

More information

Lecture 14: Other Galaxies A2020 Prof. Tom Megeath. The Milky Way in the Infrared 3/17/10. NGC 7331: the Milky Way s Twins. Spiral Galaxy bulge halo

Lecture 14: Other Galaxies A2020 Prof. Tom Megeath. The Milky Way in the Infrared 3/17/10. NGC 7331: the Milky Way s Twins. Spiral Galaxy bulge halo Lecture 14: Other Galaxies A2020 Prof. Tom Megeath Our Galaxy: Side View We see our galaxy edge-on Primary features: Disk: young and old stars where we live. Bulge: older stars Halo: oldest stars, globular

More information

The Milky Way. Mass of the Galaxy, Part 2. Mass of the Galaxy, Part 1. Phys1403 Stars and Galaxies Instructor: Dr. Goderya

The Milky Way. Mass of the Galaxy, Part 2. Mass of the Galaxy, Part 1. Phys1403 Stars and Galaxies Instructor: Dr. Goderya Foundations Chapter of Astronomy 15 13e Our Milky Way Seeds Phys1403 Stars and Galaxies Instructor: Dr. Goderya Selected Topics in Chapter 15 A view our Milky Way? The Size of our Milky Way The Mass of

More information

Galaxies Guiding Questions

Galaxies Guiding Questions Galaxies Guiding Questions How did astronomers first discover other galaxies? How did astronomers first determine the distances to galaxies? Do all galaxies have spiral arms, like the Milky Way? How do

More information

ASTRONOMY II Spring 1995 FINAL EXAM. Monday May 8th 2:00pm

ASTRONOMY II Spring 1995 FINAL EXAM. Monday May 8th 2:00pm ASTRONOMY II - 79202 Spring 1995 FINAL EXAM Monday May 8th 2:00pm Name: You have three hours to complete this exam. I suggest you read through the entire exam before you spend too much time on any one

More information

Survey of Astrophysics A110

Survey of Astrophysics A110 Goals: Galaxies To determine the types and distributions of galaxies? How do we measure the mass of galaxies and what comprises this mass? How do we measure distances to galaxies and what does this tell

More information

The Universe o. Galaxies. The Universe of. Galaxies. Ajit Kembhavi IUCAA

The Universe o. Galaxies. The Universe of. Galaxies. Ajit Kembhavi IUCAA Hello! The Universe of Galaxies The Universe o Galaxies Ajit Kembhavi IUCAA Galaxies: Stars: ~10 11 Mass: ~10 11 M Sun Contain stars, gas and dust, possibly a supermassive black hole at the centre. Much

More information

The Milky Way & Galaxies

The Milky Way & Galaxies The Milky Way & Galaxies The Milky Way Appears as a milky band of light across the sky A small telescope reveals that it is composed of many stars (Galileo again!) Our knowledge of the Milky Way comes

More information

Page # Astronomical Distances. Lecture 2. Astronomical Distances. Cosmic Distance Ladder. Distance Methods. Size of Earth

Page # Astronomical Distances. Lecture 2. Astronomical Distances. Cosmic Distance Ladder. Distance Methods. Size of Earth Size of Astronomical istances ecture 2 Astronomical istances istance to the Moon (1 sec) istance to the Sun (8 min) istance to other stars (years) istance to centre of our Galaxy ( 30,000 yr to centre)

More information

Set 5: Expansion of the Universe

Set 5: Expansion of the Universe Set 5: Expansion of the Universe Cosmology Study of the origin, contents and evolution of the universe as a whole Expansion rate and history Space-time geometry Energy density composition Origin of structure

More information

The Next 2-3 Weeks. Important to read through Chapter 17 (Relativity) before I start lecturing on it.

The Next 2-3 Weeks. Important to read through Chapter 17 (Relativity) before I start lecturing on it. The Next 2-3 Weeks [27.1] The Extragalactic Distance Scale. [27.2] The Expansion of the Universe. [29.1] Newtonian Cosmology [29.2] The Cosmic Microwave Background [17] General Relativity & Black Holes

More information

Lecture Outlines. Chapter 24. Astronomy Today 8th Edition Chaisson/McMillan Pearson Education, Inc.

Lecture Outlines. Chapter 24. Astronomy Today 8th Edition Chaisson/McMillan Pearson Education, Inc. Lecture Outlines Chapter 24 Astronomy Today 8th Edition Chaisson/McMillan Chapter 24 Galaxies Units of Chapter 24 24.1 Hubble s Galaxy Classification 24.2 The Distribution of Galaxies in Space 24.3 Hubble

More information

Name Midterm Exam October 20, 2017

Name Midterm Exam October 20, 2017 Name Midterm Exam October 20, 2017 This test consists of three parts. For the first and second parts, you may write your answers directly on the exam, if you wish. For the other parts, use separate sheets

More information

Lecture 25: The Cosmic Distance Scale Sections 25-1, 26-4 and Box 26-1

Lecture 25: The Cosmic Distance Scale Sections 25-1, 26-4 and Box 26-1 Lecture 25: The Cosmic Distance Scale Sections 25-1, 26-4 and Box 26-1 Key Ideas The Distance Problem Geometric Distances Trigonometric Parallaxes Luminosity Distances Standard Candles Spectroscopic Parallaxes

More information

The Milky Way Galaxy Guiding Questions

The Milky Way Galaxy Guiding Questions The Milky Way Galaxy Guiding Questions 1. What is our Galaxy? How do astronomers know where we are located within it? 2. What is the shape and size of our Galaxy? 3. How do we know that our Galaxy has

More information

The Milky Way Galaxy

The Milky Way Galaxy The Milky Way Galaxy Guiding Questions 1. What is our Galaxy? How do astronomers know where we are located within it? 2. What is the shape and size of our Galaxy? 3. How do we know that our Galaxy has

More information

The distance modulus in the presence of absorption is given by

The distance modulus in the presence of absorption is given by Problem 4: An A0 main sequence star is observed at a distance of 100 pc through an interstellar dust cloud. Furthermore, it is observed with a color index B-V = 1.5. What is the apparent visual magnitude

More information

AS1001: Galaxies and Cosmology

AS1001: Galaxies and Cosmology AS1001: Galaxies and Cosmology Keith Horne kdh1@st-and.ac.uk http://www-star.st-and.ac.uk/~kdh1/eg/eg.html Text: Kutner Astronomy:A Physical Perspective Chapters 17-21 Cosmology Today Blah Title Current

More information

The Extragalactic Distance Scale

The Extragalactic Distance Scale One of the important relations in Astronomy. It lets us Measure the distance to distance objects. Each rung on the ladder is calibrated using lower-rung calibrations. Distance Objects Technique 1-100 AU

More information

Clicker Question: Clicker Question: Clicker Question: Clicker Question: What is the remnant left over from a Type Ia (carbon detonation) supernova:

Clicker Question: Clicker Question: Clicker Question: Clicker Question: What is the remnant left over from a Type Ia (carbon detonation) supernova: Test 3 results D C Grades posted in cabinet and Grades posted on-line B A F If you are not properly registered then come see me for your grade What is the ultimate origin of the elements heavier than helium

More information

Chapter 19 Galaxies. Hubble Ultra Deep Field: Each dot is a galaxy of stars. More distant, further into the past. halo

Chapter 19 Galaxies. Hubble Ultra Deep Field: Each dot is a galaxy of stars. More distant, further into the past. halo Chapter 19 Galaxies Hubble Ultra Deep Field: Each dot is a galaxy of stars. More distant, further into the past halo disk bulge Barred Spiral Galaxy: Has a bar of stars across the bulge Spiral Galaxy 1

More information

Astronomy 102 Lab: Distances to Galaxies

Astronomy 102 Lab: Distances to Galaxies Name: Astronomy 102 Lab: Distances to Galaxies You will access your textbook for this lab. Pre-Lab Assignment: As we began to talk about stars beyond the Sun, one of the most important pieces of information

More information

The Milky Way. Overview: Number of Stars Mass Shape Size Age Sun s location. First ideas about MW structure. Wide-angle photo of the Milky Way

The Milky Way. Overview: Number of Stars Mass Shape Size Age Sun s location. First ideas about MW structure. Wide-angle photo of the Milky Way Figure 70.01 The Milky Way Wide-angle photo of the Milky Way Overview: Number of Stars Mass Shape Size Age Sun s location First ideas about MW structure Figure 70.03 Shapely (~1900): The system of globular

More information

SUPPLEMENTARY INFORMATION

SUPPLEMENTARY INFORMATION 1. Identification of classical Cepheids: We identified three classical Cepheids amongst the 45 short-period variables discovered. Our sample includes classical Cepheids, type II Cepheids, eclipsing binaries

More information

Science Olympiad Astronomy C Division Event Golden Gate Invitational

Science Olympiad Astronomy C Division Event Golden Gate Invitational Science Olympiad Astronomy C Division Event Golden Gate Invitational University of California, Berkeley Berkeley, CA February 9, 2019 Team Number: Team Name: Instructions: 1) Please turn in all materials

More information

Globular Clusters in M87

Globular Clusters in M87 Globular Clusters in M87 Tutor: Søren S. Larsen First NEON Archive Observing School 2004 Avet Harutyunyan Saskia Hekker Anatoliy Ivantsov Loredana Vetere Contents Globular Clusters Introduction Data Retrieving

More information

ASTR 1120 General Astronomy: Stars & Galaxies

ASTR 1120 General Astronomy: Stars & Galaxies ASTR 1120 General Astronomy: Stars & Galaxies!NNOUNCEMENTS HOMEWORK #6 DUE TODAY, by 5pm HOMEWORK #7 DUE Nov. 10, by 5pm Dark matter halo for galaxies Dark matter extends beyond visible part of the galaxy

More information

GLOBAL PROPERTIES OF THE GLOBULAR CLUSTER SYSTEMS OF FOUR SPIRAL GALAXIES

GLOBAL PROPERTIES OF THE GLOBULAR CLUSTER SYSTEMS OF FOUR SPIRAL GALAXIES The Astronomical Journal, 134:1403 1418, 2007 October # 2007. The American Astronomical Society. All rights reserved. Printed in U.S.A. GLOBAL PROPERTIES OF THE GLOBULAR CLUSTER SYSTEMS OF FOUR SPIRAL

More information

Exam 4 Review EXAM COVERS LECTURES 22-29

Exam 4 Review EXAM COVERS LECTURES 22-29 Exam 4 Review EXAM COVERS LECTURES 22-29 Theoretically is there a center of the universe? Is there an edge? Do we know where Earth is on this? There is no center to the Universe, What kind of light we

More information

The Milky Way. Finding the Center. Milky Way Composite Photo. Finding the Center. Milky Way : A band of and a. Milky Way

The Milky Way. Finding the Center. Milky Way Composite Photo. Finding the Center. Milky Way : A band of and a. Milky Way The Milky Way Milky Way : A band of and a The band of light we see is really 100 billion stars Milky Way probably looks like Andromeda. Milky Way Composite Photo Milky Way Before the 1920 s, astronomers

More information

Astronomy 113. Dr. Joseph E. Pesce, Ph.D. Distances & the Milky Way. The Curtis View. Our Galaxy. The Shapley View 3/27/18

Astronomy 113. Dr. Joseph E. Pesce, Ph.D. Distances & the Milky Way. The Curtis View. Our Galaxy. The Shapley View 3/27/18 Astronomy 113 Dr. Joseph E. Pesce, Ph.D. Distances & the Milky Way 14-2 Historical Overview: the Curtis-Shapley Debate ³What is the size of our galaxy? ³What is the nature of spiral nebula? The Curtis

More information

Astronomy 113. Dr. Joseph E. Pesce, Ph.D. Dr. Joseph E. Pesce, Ph.D.

Astronomy 113. Dr. Joseph E. Pesce, Ph.D. Dr. Joseph E. Pesce, Ph.D. Astronomy 113 Dr. Joseph E. Pesce, Ph.D. Distances & the Milky Way Historical Overview: the Curtis-Shapley Debate ³What is the size of our galaxy? ³What is the nature of spiral nebula? 14-2 ³Occurred in

More information

4/10/18. Our wide world (universe) of Galaxies. Spirals ~80% of galaxies

4/10/18.  Our wide world (universe) of Galaxies. Spirals ~80% of galaxies ASTR 1040: Stars & Galaxies Prof. Juri Toomre TAs: Peri Johnson, Ryan Horton Lecture 23 Tues 10 Apr 2018 zeus.colorado.edu/astr1040-toomre Our wide world (universe) of Galaxies The rich range of galaxies:

More information

The Milky Way Galaxy and Interstellar Medium

The Milky Way Galaxy and Interstellar Medium The Milky Way Galaxy and Interstellar Medium Shape of the Milky Way Uniform distribution of stars in a band across the sky lead Thomas Wright, Immanuel Kant, and William Herschel in the 18th century to

More information

ASTR 1120 General Astronomy: Stars & Galaxies

ASTR 1120 General Astronomy: Stars & Galaxies ASTR 1120 General Astronomy: Stars & Galaxies!NNOUNCEMENTS HOMEWORK #6 DUE TODAY, by 5pm HOMEWORK #7 DUE Nov. 10, by 5pm Dark matter halo for galaxies REVIEW Dark matter extends beyond visible part of

More information

Astronomy A BEGINNER S GUIDE TO THE UNIVERSE EIGHTH EDITION

Astronomy A BEGINNER S GUIDE TO THE UNIVERSE EIGHTH EDITION Astronomy A BEGINNER S GUIDE TO THE UNIVERSE EIGHTH EDITION CHAPTER 14 The Milky Way Galaxy Lecture Presentation 14.0 the Milky Way galaxy How do we know the Milky Way exists? We can see it even though

More information

Chapter 25: Galaxy Clusters and the Structure of the Universe

Chapter 25: Galaxy Clusters and the Structure of the Universe Chapter 25: Galaxy Clusters and the Structure of the Universe Distribution of galaxies Evolution of galaxies Study of distant galaxies Distance derived from redshift Hubble s constant age of the Universe:

More information

Tuesday, Thursday 2:30-3:45 pm. Astronomy 100. Tom Burbine

Tuesday, Thursday 2:30-3:45 pm.   Astronomy 100. Tom Burbine Astronomy 100 Tuesday, Thursday 2:30-3:45 pm Tom Burbine tburbine@mtholyoke.edu www.xanga.com/astronomy100 OWL assignment (Due Today) There is be an OWL assignment due on Thursday April 14 at 11:59 pm.

More information

The King's University College Astronomy 201 Mid-Term Exam Solutions

The King's University College Astronomy 201 Mid-Term Exam Solutions The King's University College Astronomy 201 Mid-Term Exam Solutions Instructions: The exam consists of two sections. Part A is 20 multiple choice questions - please record answers on the sheet provided.

More information

Galaxies and Cosmology

Galaxies and Cosmology 4/28/17 The Discovery of Galaxies Up to the 1920 s, astronomers were not sure exactly how far away galaxies were, and thus didn t know how big they are! Spiral Nebulae could be assumed to be inside our

More information

The Extragalactic Distance Scale

The Extragalactic Distance Scale One of the important relations in Astronomy. It lets us Measure the distance to distance objects. Each rung on the ladder is calibrated using lower-rung calibrations. Distance Objects Technique 1-100 AU

More information

Cosmic Distance Determinations

Cosmic Distance Determinations Cosmic Distance Determinations Radar (works for inner solar system) Parallax D(pc) = 1 p(arcsec) GAIA satellite (2013) 20 micro-arcsec resolution! Thus D < 10 kpc Beyond Parallax: Standard Candles Use

More information

Universe Now. 9. Interstellar matter and star clusters

Universe Now. 9. Interstellar matter and star clusters Universe Now 9. Interstellar matter and star clusters About interstellar matter Interstellar space is not completely empty: gas (atoms + molecules) and small dust particles. Over 10% of the mass of the

More information

There are three main ways to derive q 0 :

There are three main ways to derive q 0 : Measuring q 0 Measuring the deceleration parameter, q 0, is much more difficult than measuring H 0. In order to measure the Hubble Constant, one needs to derive distances to objects at 100 Mpc; this corresponds

More information

Exam # 3 Tue 12/06/2011 Astronomy 100/190Y Exploring the Universe Fall 11 Instructor: Daniela Calzetti

Exam # 3 Tue 12/06/2011 Astronomy 100/190Y Exploring the Universe Fall 11 Instructor: Daniela Calzetti Exam # 3 Tue 12/06/2011 Astronomy 100/190Y Exploring the Universe Fall 11 Instructor: Daniela Calzetti INSTRUCTIONS: Please, use the `bubble sheet and a pencil # 2 to answer the exam questions, by marking

More information

Lecture 2: Galaxy types, spectra

Lecture 2: Galaxy types, spectra Lecture 2: Galaxy types, spectra Galaxies AS 3011 1 Hubble tuning fork this is really just descriptive, but Hubble suggested galaxies evolve from left to right in this picture not unreasonable, perhaps

More information

Lecture 2: Galaxy types, spectra. Galaxies AS

Lecture 2: Galaxy types, spectra. Galaxies AS Lecture 2: Galaxy types, spectra Galaxies AS 3011 1 Hubble tuning fork this is really just descriptive, but Hubble suggested galaxies evolve from left to right in this picture not unreasonable, perhaps

More information

Allan Sandage and the Cosmic Expansion

Allan Sandage and the Cosmic Expansion Allan Sandage and the Cosmic Expansion The Fundamental Cosmic Distance Scale Conference, Naples May 2 6, 2011 G. A. Tammann Allan Sandage a mentor, a collaborator, a friend for 47 years G. A. Tammann A.

More information

Lecture 33: Announcements

Lecture 33: Announcements Lecture 33: Announcements 1) Pick up graded hwk 5. Good job: Jessica, Jessica, and Elizabeth for a 100% score on hwk 5 and the other 25% of the class with an A. 2) Article and homework 7 were posted on

More information

Red giants in the halo of the SO galaxy NGC 3115: a distance and a bimodal metallicity distribution

Red giants in the halo of the SO galaxy NGC 3115: a distance and a bimodal metallicity distribution Mon. Not. R. Astron. Soc. 286, 771-776 (1997) Red giants in the halo of the SO galaxy NGC 3115: a distance and a bimodal metallicity distribution Rebecca A. W. Elson* Institute of Astronomy, Madingley

More information

Chapter 20: Galaxies and the Foundation of Modern Cosmology

Chapter 20: Galaxies and the Foundation of Modern Cosmology Chapter 20 Lecture Chapter 20: Galaxies and the Foundation of Modern Cosmology Galaxies and the Foundation of Modern Cosmology 20.1 Islands of Stars Our goals for learning: How are the lives of galaxies

More information

Observations of Globular Cluster Systems of Giant Galaxies

Observations of Globular Cluster Systems of Giant Galaxies Observations of Globular Cluster Systems of Giant Galaxies Katherine Rhode Indiana University 38 x 38 R image of Virgo elliptical NGC 4472 KITP Conference January 2009 Observations of Globular Cluster

More information

Stars, Galaxies & the Universe Lecture Outline

Stars, Galaxies & the Universe Lecture Outline Stars, Galaxies & the Universe Lecture Outline A galaxy is a collection of 100 billion stars! Our Milky Way Galaxy (1)Components - HII regions, Dust Nebulae, Atomic Gas (2) Shape & Size (3) Rotation of

More information

Our Galaxy. Milky Way Galaxy = Sun + ~100 billion other stars + gas and dust. Held together by gravity! The Milky Way with the Naked Eye

Our Galaxy. Milky Way Galaxy = Sun + ~100 billion other stars + gas and dust. Held together by gravity! The Milky Way with the Naked Eye Our Galaxy Milky Way Galaxy = Sun + ~100 billion other stars + gas and dust Held together by gravity! The Milky Way with the Naked Eye We get a special view of our own galaxy because we are part of it!

More information

Astr 5465 Feb. 13, 2018 Distribution & Classification of Galaxies Distribution of Galaxies

Astr 5465 Feb. 13, 2018 Distribution & Classification of Galaxies Distribution of Galaxies Astr 5465 Feb. 13, 2018 Distribution & Classification of Galaxies Distribution of Galaxies Faintest galaxies are distributed ~ uniformly over the sky except for the Galactic plane (zone of avoidance) Brighter

More information

Normal Galaxies ASTR 2120 Sarazin

Normal Galaxies ASTR 2120 Sarazin Normal Galaxies ASTR 2120 Sarazin Test #2 Monday, April 8, 11-11:50 am ASTR 265 (classroom) Bring pencils, paper, calculator You may not consult the text, your notes, or any other materials or any person

More information

A100H Exploring the Universe: Discovering Galaxies. Martin D. Weinberg UMass Astronomy

A100H Exploring the Universe: Discovering Galaxies. Martin D. Weinberg UMass Astronomy A100H Exploring the Universe: Discovering Galaxies Martin D. Weinberg UMass Astronomy astron100h-mdw@courses.umass.edu April 05, 2016 Read: Chap 19 04/05/16 slide 1 Exam #2 Returned by next class meeting

More information

Laboratory: Milky Way

Laboratory: Milky Way Department of Physics and Geology Laboratory: Milky Way Astronomy 1402 Equipment Needed Quantity Equipment Needed Quantity Milky Way galaxy Model 1 Ruler 1 1.1 Our Milky Way Part 1: Background Milky Way

More information

Chapter 15 2/19/2014. Lecture Outline Hubble s Galaxy Classification. Normal and Active Galaxies Hubble s Galaxy Classification

Chapter 15 2/19/2014. Lecture Outline Hubble s Galaxy Classification. Normal and Active Galaxies Hubble s Galaxy Classification Lecture Outline Chapter 15 Normal and Active Galaxies Spiral galaxies are classified according to the size of their central bulge. Chapter 15 Normal and Active Galaxies Type Sa has the largest central

More information

Chapter 20 Galaxies and the Foundation of Modern Cosmology Pearson Education, Inc.

Chapter 20 Galaxies and the Foundation of Modern Cosmology Pearson Education, Inc. Chapter 20 Galaxies and the Foundation of Modern Cosmology 20.1 Islands of Stars Our goals for learning: How are the lives of galaxies connected with the history of the universe? What are the three major

More information

A 103 Notes, Week 14, Kaufmann-Comins Chapter 15

A 103 Notes, Week 14, Kaufmann-Comins Chapter 15 NEARBY GALAXIES I. Brief History A 103 Notes, Week 14, Kaufmann-Comins Chapter 15 A. Kant B. Curtis-Shapley debate C. Distance to Andromeda II. Classification of nearby galaxies: Spirals, Ellipticals,

More information

This Week in Astronomy

This Week in Astronomy Homework #8 Due Wednesday, April 18, 11:59PM Covers Chapters 15 and 16 Estimated time to complete: 40 minutes Read chapters, review notes before starting This Week in Astronomy Credit: NASA/JPL-Caltech

More information

Galaxies & Introduction to Cosmology

Galaxies & Introduction to Cosmology Galaxies & Introduction to Cosmology Other Galaxies: How many are there? Hubble Deep Field Project 100 hour exposures over 10 days Covered an area of the sky about 1/100 the size of the full moon Probably

More information

Chapter 19 Reading Quiz Clickers. The Cosmic Perspective Seventh Edition. Our Galaxy Pearson Education, Inc.

Chapter 19 Reading Quiz Clickers. The Cosmic Perspective Seventh Edition. Our Galaxy Pearson Education, Inc. Reading Quiz Clickers The Cosmic Perspective Seventh Edition Our Galaxy 19.1 The Milky Way Revealed What does our galaxy look like? How do stars orbit in our galaxy? Where are globular clusters located

More information

The Discovery of Other Galaxies. 24. Normal Galaxies

The Discovery of Other Galaxies. 24. Normal Galaxies 24. Normal Galaxies The discovery of other galaxies Edwin Hubble proved galaxies are very distant Edwin Hubble classified galaxies by shape Methods for determining distances to galaxies The Hubble Law

More information

Big Galaxies Are Rare! Cepheid Distance Measurement. Clusters of Galaxies. The Nature of Galaxies

Big Galaxies Are Rare! Cepheid Distance Measurement. Clusters of Galaxies. The Nature of Galaxies Big Galaxies Are Rare! Potato Chip Rule: More small things than large things Big, bright spirals are easy to see, but least common Dwarf ellipticals & irregulars are most common Faint, hard to see Mostly

More information

A100 Exploring the Universe: The Milky Way as a Galaxy. Martin D. Weinberg UMass Astronomy

A100 Exploring the Universe: The Milky Way as a Galaxy. Martin D. Weinberg UMass Astronomy A100 Exploring the Universe: The Milky Way as a Galaxy Martin D. Weinberg UMass Astronomy astron100-mdw@courses.umass.edu November 12, 2014 Read: Chap 19 11/12/14 slide 1 Exam #2 Returned and posted tomorrow

More information

Galaxy classification

Galaxy classification Galaxy classification Questions of the Day What are elliptical, spiral, lenticular and dwarf galaxies? What is the Hubble sequence? What determines the colors of galaxies? Top View of the Milky Way The

More information

Galaxies. Galaxy Diversity. Galaxies, AGN and Quasars. Physics 113 Goderya

Galaxies. Galaxy Diversity. Galaxies, AGN and Quasars. Physics 113 Goderya Galaxies, AGN and Quasars Physics 113 Goderya Chapter(s): 16 and 17 Learning Outcomes: Galaxies Star systems like our Milky Way Contain a few thousand to tens of billions of stars. Large variety of shapes

More information

Star systems like our Milky Way. Galaxies

Star systems like our Milky Way. Galaxies Galaxies Star systems like our Milky Way Galaxies Contain a few thousand to tens of billions of stars,as well as varying amounts of gas and dust Large variety of shapes and sizes Gas and Dust in

More information

Beyond Our Solar System Chapter 24

Beyond Our Solar System Chapter 24 Beyond Our Solar System Chapter 24 PROPERTIES OF STARS Distance Measuring a star's distance can be very difficult Stellar parallax Used for measuring distance to a star Apparent shift in a star's position

More information

The Milky Way Galaxy. Some thoughts. How big is it? What does it look like? How did it end up this way? What is it made up of?

The Milky Way Galaxy. Some thoughts. How big is it? What does it look like? How did it end up this way? What is it made up of? Some thoughts The Milky Way Galaxy How big is it? What does it look like? How did it end up this way? What is it made up of? Does it change 2 3 4 5 This is not a constant zoom The Milky Way Almost everything

More information

Exploring the stellar population of nearby and high redshift galaxies with ELTs. Marco Gullieuszik INAF - Padova Observatory

Exploring the stellar population of nearby and high redshift galaxies with ELTs. Marco Gullieuszik INAF - Padova Observatory Exploring the stellar population of nearby and high redshift galaxies with ELTs INAF - Padova Observatory The team R. Falomo L. Greggio M. Uslenghi INAF Osservatorio Astronomico di Padova INAF Osservatorio

More information

ASTR 101 Introduction to Astronomy: Stars & Galaxies

ASTR 101 Introduction to Astronomy: Stars & Galaxies ASTR 101 Introduction to Astronomy: Stars & Galaxies If your clicker grade on BlackBoard is 0 and you have been in class, please send your clicker # to TA Cameron Clarke for checking The Milky Way Size

More information

11/8/18. Tour of Galaxies. Our Schedule

11/8/18. Tour of Galaxies. Our Schedule ASTR 1040: Stars & Galaxies Super-bubble blowout in NGC 3709 Prof. Juri Toomre TAs: Ryan Horton, Loren Matilsky Lecture 22 Thur 8 Nov 2018 zeus.colorado.edu/astr1040-toomre Tour of Galaxies Look at complex

More information

Chapter 20 Lecture. The Cosmic Perspective. Seventh Edition. Galaxies and the Foundation of Modern Cosmology Pearson Education, Inc.

Chapter 20 Lecture. The Cosmic Perspective. Seventh Edition. Galaxies and the Foundation of Modern Cosmology Pearson Education, Inc. Chapter 20 Lecture The Cosmic Perspective Seventh Edition Galaxies and the Foundation of Modern Cosmology 20.1 Islands of Stars Our goals for learning: How do galaxies evolve? What are the three major

More information

Astronomy 422! Lecture 7: The Milky Way Galaxy III!

Astronomy 422! Lecture 7: The Milky Way Galaxy III! Astronomy 422 Lecture 7: The Milky Way Galaxy III Key concepts: The supermassive black hole at the center of the Milky Way Radio and X-ray sources Announcements: Test next Tuesday, February 16 Chapters

More information

M31 - Andromeda Galaxy M110 M32

M31 - Andromeda Galaxy M110 M32 UNIT 4 - Galaxies XIV. The Milky Way galaxy - a huge collection of millions or billions of stars, gas, and dust, isolated in space and held together by its own gravity M110 M31 - Andromeda Galaxy A. Structure

More information

Galaxies. With a touch of cosmology

Galaxies. With a touch of cosmology Galaxies With a touch of cosmology Types of Galaxies Spiral Elliptical Irregular Spiral Galaxies Spiral Galaxies Disk component where the spiral arms are Interstellar medium Star formation Spheroidal

More information

galaxies: individual: NGC 6946 galaxies: spiral galaxies:

galaxies: individual: NGC 6946 galaxies: spiral galaxies: Baltic Astronomy, vol. 25, 369 376, 2016 UNUSUAL OBJECTS IN THE SPIRAL GALAXY NGC 6946 Yu. N. Efremov Sternberg Astronomical Institute, M. V. Lomonosov Moscow State University, Universitetskij pr. 13,

More information

Obtain one of the laminated sheets, and classify the numbered objects by color (hopefully obvious) and by shape:

Obtain one of the laminated sheets, and classify the numbered objects by color (hopefully obvious) and by shape: Astronomy 100 Name(s): Exercise 8: Galaxies and the Hubble Law The large-scale structure of the universe is governed by gravity. The Sun orbits the center of our galaxy, the Milky Way. The Milky Way, in

More information

2019 Astronomy Team Selection Test

2019 Astronomy Team Selection Test 2019 Astronomy Team Selection Test Acton-Boxborough Regional High School Written by Antonio Frigo Do not flip over this page until instructed. Instructions You will have 45 minutes to complete this exam.

More information

Chapter 20 Lecture. The Cosmic Perspective Seventh Edition. Galaxies and the Foundation of Modern Cosmology Pearson Education, Inc.

Chapter 20 Lecture. The Cosmic Perspective Seventh Edition. Galaxies and the Foundation of Modern Cosmology Pearson Education, Inc. Chapter 20 Lecture The Cosmic Perspective Seventh Edition Galaxies and the Foundation of Modern Cosmology Galaxies and the Foundation of Modern Cosmology 20.1 Islands of Stars Our goals for learning: How

More information

AST1100 Lecture Notes

AST1100 Lecture Notes AST1100 Lecture Notes 11 12 The cosmic distance ladder How do we measure the distance to distant objects in the universe? There are several methods available, most of which suffer from large uncertainties.

More information

ASTR 200 : Lecture 22 Structure of our Galaxy

ASTR 200 : Lecture 22 Structure of our Galaxy ASTR 200 : Lecture 22 Structure of our Galaxy 1 The 'Milky Way' is known to all cultures on Earth (perhaps, unfortunately, except for recent city-bound dwellers) 2 Fish Eye Lens of visible hemisphere (but

More information