Class #4 11 September 2008
|
|
- Tamsin Perkins
- 6 years ago
- Views:
Transcription
1 Class #4 11 September 2008
2 Review Stellar evolution/nucleosynthesis/h-r diagrams Phases of the Interstellar Medium The Hydrogen Atom
3 H-R diagram for 47 Tuc Evolution+nucleosynt hesis each box is a different burning stage Could you sketch the H-R diagram of this cluster and label all of the major burning stages?
4 Stellar initial mass function dn = N o ξ(m)dm dm M ξ(m) = total mass of burst/episode Observationally: ξ(m) goes as M Slight variation with mass, according to some Salpeter IMF
5 Density of any locale on a CMD is a function of IMF, SFR, mass, and age C(M V, V-I) = ξ(log m, t) x SFR(t) dt dlogm Small mass bin (i.e. single mass) Constant IMF (ξ) Can recover star formation history from a complex CMD Statistical Approach What is the probability that a certain disitrbution of points on the CMD came from one particular set of stellar evolution models (Tolstoy & Saha 1996)
6 Optically visible components Dark band through center of the MW Diffuse emission regions Verification Cluster diameter vs luminosity distances Non-varying absorption lines in binaries NGC 891 viewed edge-on
7 Phase Temp. n f.f. Diag. Cold low CO Cool low HI Warm high HI Warm high Hα Hot high X-ray Relativistic?? High Synch.
8 Cold molecular line spectroscopy with radio/mm wave telescopes. CO has a dipole moment, transitions due to ang mo quantum number (e.g. J=1 0 at 2.6mm) I CO = dv T A (2.6mm line of 12 CO) T A is the antenna temperature so that P = kt A Conversion to H 2 Assume CO linewidth is gravitational, so that the velocity dispersion is σ = (GM/R) 1/2 (so I CO is proportional to mass) X N(H 2 )/I CO ~ 2.3 x (is this really the same everywhere???) Other methods include UV spectroscopy to get H 2, even more complex molecules (e.g. HCN)
9 di ν /ds = (hν/4π)[n 2 A 21 (n 1 B 12 n 2 B 21 )(4πI ν /c)] n = # density of atoms A 21 = prob. for spontaneous emission B 12 = prob. for stimulated emission B 21 = prob. for absorption di ν /dτ ν + I ν = S v (S = source function) I ν (τ) = I ν (0)e -τ + S ν (1-e -τ ) Assume thermodynamic equilibrium so the source function is the Planck function and level populations is governed by: n(2)/n(1) = g(2)/g(1) x exp(-hν/kt)
10 A 21 = (8πhν 3 /c 3 )B 21 g 1 B 12 = g 2 B 21 Assume hν << kt So B v (T) = (2kTν 2 /c 2 ) So. I ν (τ) = I ν (0)e -τ + (2kTν 2 /c 2 )(1-e -τ ) T B (c 2 /2kν 2 )I ν ; substitute this in and get T B (τ) = T B (0) e -τ + (1-e - τ )T
11 Optically thin (τ << 1) T B = τt Optically thick (τ >> 1) T B = T
12 Hyperfine transition in the ground state from the interaction between the spins of the electron and proton. ΔE = 6 x 10-6 ev freq = GHz Lifetime of excited level is long (10 7 yr) so collisional excitation and de-excitation is fast compared to spontaneous decay. Level populations depend only on kinetic temperature of the gas. Optical depth = (B 12 h 2 ν 2 /ck)n 1 /T N 1 = ds n 1 = column density of H atoms capable of absorbing at frequency, ν With some more approximations and rearranging we can get a famous relationship N H = 1.82 x dv T B (if optically thin), and M H = 2.36 x 10 5 D 2 S(v) dv, where S(v) is in Jy km s -1
13 Largely yields emission lines via recombination into various primary quantum levels Hα (656.3nm) arises from transition from n=3 to n=2. See example from M33 Also a few higher ionization states of heavier nuclei in the UV (e.g. CIV).
14
15
16 D = 950 kpc, SFR = 0.03 M 0 yr -1, high density of W-R stars Thurow & Wilcots 2005
17 HI clouds in IC 10 main star-forming regions
18
19 Gas heated to 10 6 K (probably by SNe) Powerful probe of mass distribution in galaxy clusters Detected via X-ray emission Point source population Diffuse hot gas Emission via Brehmstrahlung Emission lines of highly ionized species
20 McKee & Ostriker (1977): diffuse hot phase of the ISM with a filling factor of 100% Early detection of X-ray emitting superbubbles in the Milky Way: Sco-Cen, Orion-Eridanus (McCammon et al. '83, McCammon & Sanders '90) Origin of Soft X-Ray background MWG: local ISM + hot galactic halo Local Group: hot intergalactic medium Extragalactic: (un)resolved AGN + E galaxies
21 Radius: pc Temperature: ~ K Thermal pressure: p/k = 10 4 cm -3 K N(HI) = 6 x cm -2 (derived from soft X-ray absorption) Origin of the Local Bubble hot gas w/ 100% filling factor? diffuse gas reheated by recent SNe? a series of 2-5 SNe a few million years ago? an extension of nearby superbubble?
22 Einstein: 1' resolution M101 (McCammon & Sanders 1984) L X (diffuse) ~ erg s -1 ROSAT (PSPC): 1.'8 resolution, kev M101, N3184, N4395, N5055, N4736 (Cui et al. 1996) CXO: <1 over 8 arcminutes XMM/Newton: 15 over 30 arcminutes
23 X-ray emission Hα emission (WIYN) (Doane et al. 2007)
24 LMC Superbubbles: 1.7-9(10 6 )K Orion-Eri.: 3.3(10 6 )K N. P. Spur: 3.0(10 6 )K Sco-Cen: 4.6(10 6 )K NGC3631: 1,3(10 6 )K NGC6946: 2,7(10 6 )K M101:2,8(10 6 )K N253(halo): 4(10 6 )K M82(halo):3,4(10 6 )K Spirals are best fit with two temperature models of hot gas, but there is variation in the high temperature and surface brightness.
25 Diffuse emission is highly correlated with both spiral arms and HII regions Bulk of the diffuse emission arises from less than 25% of the area of the disk X-ray spectra are best fit with a two temperature model There is variation in the surface brightnesses between galaxies and variation in the temperature of the hot component
26 stellar winds + SNe dump erg into ISM creates hot bubble surrounded by swept up ISM and circumstellar matter gas heated by inward moving shock X-ray emission should be aligned with HI holes growth of chimneys (as means of getting hot gas into the halo) Norman & Ikeuchi
27 Stellar winds/sne drive expanding bubbles into ISM R s = 100(N * E 51 /n 0 ) 1/5 t 7 3/5 pc (McCray & Kafatos 1987) V s = L W 1/5 n 0-1/5 t -2/5 Reverse shock heats bubble to K X-ray emitting Shell includes swept up ISM, dense neutral gas, possibly accelerated particles Ultimate fate Shell/bubble expands until P bubble = P ISM+IGM Breaks out of disk if P bubble > P ambient, V shell > V escape Shell accelerates in density gradient R(t) ~ r c + [1 + (3/3-w) 1/2 ]v i t n(r) ~ r -w
28 Concentrated SNe Nuclear starburst complete blowout of the ISM
Gas 1: Molecular clouds
Gas 1: Molecular clouds > 4000 known with masses ~ 10 3 to 10 5 M T ~ 10 to 25 K (cold!); number density n > 10 9 gas particles m 3 Emission bands in IR, mm, radio regions from molecules comprising H,
More informationComponents of Galaxies Gas The Importance of Gas
Components of Galaxies Gas The Importance of Gas Fuel for star formation (H 2 ) Tracer of galaxy kinematics/mass (HI) Tracer of dynamical history of interaction between galaxies (HI) The Two-Level Atom
More informationStars, 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 informationSome HI is in reasonably well defined clouds. Motions inside the cloud, and motion of the cloud will broaden and shift the observed lines!
Some HI is in reasonably well defined clouds. Motions inside the cloud, and motion of the cloud will broaden and shift the observed lines Idealized 21cm spectra Example observed 21cm spectra HI densities
More informationThe Birth Of Stars. How do stars form from the interstellar medium Where does star formation take place How do we induce star formation
Goals: The Birth Of Stars How do stars form from the interstellar medium Where does star formation take place How do we induce star formation Interstellar Medium Gas and dust between stars is the interstellar
More informationDiffuse Interstellar Medium
Diffuse Interstellar Medium Basics, velocity widths H I 21-cm radiation (emission) Interstellar absorption lines Radiative transfer Resolved Lines, column densities Unresolved lines, curve of growth Abundances,
More informationGalaxy Ecosystems Adam Leroy (OSU), Eric Murphy (NRAO/IPAC) on behalf of ngvla Working Group 2
Next Generation Very Large Array Working Group 2 HI in M74: Walter+ 08 CO in M51: Schinnerer+ 13 Continuum in M82: Marvil & Owen Galaxy Ecosystems Adam Leroy (OSU), Eric Murphy (NRAO/IPAC) on behalf of
More informationThe Interstellar Medium
http://www.strw.leidenuniv.nl/~pvdwerf/teaching/ The Interstellar Medium Lecturer: Dr. Paul van der Werf Fall 2014 Oortgebouw 565, ext 5883 pvdwerf@strw.leidenuniv.nl Assistant: Kirstin Doney Huygenslaboratorium
More informationMidterm Results. The Milky Way in the Infrared. The Milk Way from Above (artist conception) 3/2/10
Lecture 13 : The Interstellar Medium and Cosmic Recycling Midterm Results A2020 Prof. Tom Megeath The Milky Way in the Infrared View from the Earth: Edge On Infrared light penetrates the clouds and shows
More informationGalactic Supershells and GSH Vanessa A. Moss Parkes 50th Symposium 3rd November
Galactic Supershells and GSH 006-15+7 Vanessa A. Moss Parkes 50th Symposium 3rd November 2011 1 Contents Early history of supershells Discovery Early interpretation Surveys of supershells Northern hemisphere
More informationAstr 2310 Thurs. March 23, 2017 Today s Topics
Astr 2310 Thurs. March 23, 2017 Today s Topics Chapter 16: The Interstellar Medium and Star Formation Interstellar Dust and Dark Nebulae Interstellar Dust Dark Nebulae Interstellar Reddening Interstellar
More informationPhotodissociation Regions Radiative Transfer. Dr. Thomas G. Bisbas
Photodissociation Regions Radiative Transfer Dr. Thomas G. Bisbas tbisbas@ufl.edu Interstellar Radiation Field In the solar neighbourhood, the ISRF is dominated by six components Schematic sketch of the
More informationStellar Populations: Resolved vs. unresolved
Outline Stellar Populations: Resolved vs. unresolved Individual stars can be analyzed Applicable for Milky Way star clusters and the most nearby galaxies Integrated spectroscopy / photometry only The most
More informationBlack Holes and Active Galactic Nuclei
Black Holes and Active Galactic Nuclei A black hole is a region of spacetime from which gravity prevents anything, including light, from escaping. The theory of general relativity predicts that a sufficiently
More informationLec 22 Physical Properties of Molecular Clouds
Lec 22 Physical Properties of Molecular Clouds 1. Giant Molecular Clouds 2. Orion s Clouds 3. Correlations of Observed Properties 4. The X-Factor References Origins of Stars & Planetary Systems eds. Lada
More informationThe Milky Way Galaxy
1/5/011 The Milky Way Galaxy Distribution of Globular Clusters around a Point in Sagittarius About 00 globular clusters are distributed in random directions around the center of our galaxy. 1 1/5/011 Structure
More informationIonization of the Local Interstellar Cavity by Hot White Dwarfs
Ionization of the Local Interstellar Cavity by Hot White Dwarfs Barry Y. Welsh Experimental Astrophysics Group Space Sciences Lab, UC Berkeley Thanks to: Martin Barstow, Nathan Dickinson (Univ of Leicester)
More information6. Interstellar Medium. Emission nebulae are diffuse patches of emission surrounding hot O and
6-1 6. Interstellar Medium 6.1 Nebulae Emission nebulae are diffuse patches of emission surrounding hot O and early B-type stars. Gas is ionized and heated by radiation from the parent stars. In size,
More informationRadio Observations of TeV and GeV emitting Supernova Remnants
Radio Observations of TeV and GeV emitting Supernova Remnants Denis Leahy University of Calgary, Calgary, Alberta, Canada (collaborator Wenwu Tian, National Astronomical Observatories of China) outline
More informationSTAR FORMATION RATES observational overview. Ulrike Kuchner
STAR FORMATION RATES observational overview Ulrike Kuchner Remember, remember.. Outline! measurements of SFRs: - techniques to see what the SF rate is - importance of massive stars and HII regions - the
More informationLecture 2: Introduction to stellar evolution and the interstellar medium. Stars and their evolution
Lecture 2: Introduction to stellar evolution and the interstellar medium Stars and their evolution The Hertzsprung-Russell (HR) Diagram (Color-Magnitude Diagram) Apparent and Absolute Magnitudes; Dust
More informationStellar evolution Part I of III Star formation
Stellar evolution Part I of III Star formation The interstellar medium (ISM) The space between the stars is not completely empty, but filled with very dilute gas and dust, producing some of the most beautiful
More informationX-ray Radiation, Absorption, and Scattering
X-ray Radiation, Absorption, and Scattering What we can learn from data depend on our understanding of various X-ray emission, scattering, and absorption processes. We will discuss some basic processes:
More informationSpectral Line Intensities - Boltzmann, Saha Eqs.
Spectral Line Intensities - Boltzmann, Saha Eqs. Absorption in a line depends on: - number of absorbers along the line-of-sight, and -their cross section(s). Absorp. n a σl, where n a is the number of
More informationRADIO SPECTRAL LINES. Nissim Kanekar National Centre for Radio Astrophysics, Pune
RADIO SPECTRAL LINES Nissim Kanekar National Centre for Radio Astrophysics, Pune OUTLINE The importance of radio spectral lines. Equilibrium issues: kinetic, excitation, brightness temperatures. The equation
More informationSoft X-ray Emission Lines in Active Galactic Nuclei. Mat Page
Soft X-ray Emission Lines in Active Galactic Nuclei Mat Page MSSL-UCL Observations of soft X-ray line emission allow us to investigate highly ionized plasmas in galaxies and AGN. I ll start with the most
More informationPhysics Homework Set 2 Sp 2015
1) A large gas cloud in the interstellar medium that contains several type O and B stars would appear to us as 1) A) a reflection nebula. B) a dark patch against a bright background. C) a dark nebula.
More informationChapter 10 The Interstellar Medium
Chapter 10 The Interstellar Medium Guidepost You have begun your study of the sun and other stars, but now it is time to study the thin gas and dust that drifts through space between the stars. This chapter
More informationTHE GALACTIC CORONA. In honor of. Jerry Ostriker. on his 80 th birthday. Chris McKee Princeton 5/13/2017. with Yakov Faerman Amiel Sternberg
THE GALACTIC CORONA In honor of Jerry Ostriker on his 80 th birthday Chris McKee Princeton 5/13/2017 with Yakov Faerman Amiel Sternberg A collaboration that began over 40 years ago and resulted in a lifelong
More informationClicker Question: Clicker Question: What is the expected lifetime for a G2 star (one just like our Sun)?
How Long do Stars Live (as Main Sequence Stars)? A star on Main Sequence has fusion of H to He in its core. How fast depends on mass of H available and rate of fusion. Mass of H in core depends on mass
More informationAccretion Disks. 1. Accretion Efficiency. 2. Eddington Luminosity. 3. Bondi-Hoyle Accretion. 4. Temperature profile and spectrum of accretion disk
Accretion Disks Accretion Disks 1. Accretion Efficiency 2. Eddington Luminosity 3. Bondi-Hoyle Accretion 4. Temperature profile and spectrum of accretion disk 5. Spectra of AGN 5.1 Continuum 5.2 Line Emission
More informationCosmologists dedicate a great deal of effort to determine the density of matter in the universe. Type Ia supernovae observations are consistent with
Notes for Cosmology course, fall 2005 Dark Matter Prelude Cosmologists dedicate a great deal of effort to determine the density of matter in the universe Type Ia supernovae observations are consistent
More informationThree Major Components
The Milky Way Three Major Components Bulge young and old stars Disk young stars located in spiral arms Halo oldest stars and globular clusters Components are chemically, kinematically, and spatially distinct
More informationDark Matter. ASTR 333/433 Spring Today Stars & Gas. essentials about stuff we can see. First Homework on-line Due Feb. 4
Dark Matter ASTR 333/433 Spring 2016 Today Stars & Gas essentials about stuff we can see First Homework on-line Due Feb. 4 Galaxies are made of stars - D. Silva (1990) private communication Stars Majority
More informationAstro 201 Radiative Processes Problem Set 6. Due in class.
Astro 201 Radiative Processes Problem Set 6 Due in class. Readings: Hand-outs from Osterbrock; Rybicki & Lightman 9.5; however much you like of Mihalas 108 114, 119 127, 128 137 (even skimming Mihalas
More informationToday in Milky Way. Clicker on deductions about Milky Way s s stars. Why spiral arms? ASTR 1040 Accel Astro: Stars & Galaxies
ASTR 1040 Accel Astro: Stars & Galaxies Prof. Juri Toomre TA: Nick Featherstone Lecture 21 Tues 3 Apr 07 zeus.colorado.edu/astr1040-toomre toomre Superbubble NGC 3079 Today in Milky Way Look at why spiral
More informationComponents of Galaxies Stars What Properties of Stars are Important for Understanding Galaxies?
Components of Galaxies Stars What Properties of Stars are Important for Understanding Galaxies? Temperature Determines the λ range over which the radiation is emitted Chemical Composition metallicities
More informationPhotoionized Gas Ionization Equilibrium
Photoionized Gas Ionization Equilibrium Ionization Recombination H nebulae - case A and B Strömgren spheres H + He nebulae Heavy elements, dielectronic recombination Ionization structure 1 Ionization Equilibrium
More informationNumber of Stars: 100 billion (10 11 ) Mass : 5 x Solar masses. Size of Disk: 100,000 Light Years (30 kpc)
THE MILKY WAY GALAXY Type: Spiral galaxy composed of a highly flattened disk and a central elliptical bulge. The disk is about 100,000 light years (30kpc) in diameter. The term spiral arises from the external
More informationAstrophysical Quantities
Astr 8300 Resources Web page: http://www.astro.gsu.edu/~crenshaw/astr8300.html Electronic papers: http://adsabs.harvard.edu/abstract_service.html (ApJ, AJ, MNRAS, A&A, PASP, ARAA, etc.) General astronomy-type
More informationChapter 21 Galaxy Evolution. How do we observe the life histories of galaxies?
Chapter 21 Galaxy Evolution How do we observe the life histories of galaxies? Deep observations show us very distant galaxies as they were much earlier in time (old light from young galaxies). 1 Observing
More informationEnergy. mosquito lands on your arm = 1 erg. Firecracker = 5 x 10 9 ergs. 1 stick of dynamite = 2 x ergs. 1 ton of TNT = 4 x ergs
Energy mosquito lands on your arm = 1 erg Firecracker = 5 x 10 9 ergs 1 stick of dynamite = 2 x 10 13 ergs 1 ton of TNT = 4 x 10 16 ergs 1 atomic bomb = 1 x 10 21 ergs Magnitude 8 earthquake = 1 x 10 26
More informationInterstellar Medium and Star Birth
Interstellar Medium and Star Birth Interstellar dust Lagoon nebula: dust + gas Interstellar Dust Extinction and scattering responsible for localized patches of darkness (dark clouds), as well as widespread
More informationThe Physics of the Interstellar Medium
The Physics of the Interstellar Medium Ulrike Heiter Contact: 471 5970 ulrike@astro.uu.se www.astro.uu.se Matter between stars Average distance between stars in solar neighbourhood: 1 pc = 3 x 1013 km,
More informationPhysics and chemistry of the interstellar medium. Lecturers: Simon Glover, Rowan Smith Tutor: Raquel Chicharro
Physics and chemistry of the interstellar medium Lecturers: Simon Glover, Rowan Smith Tutor: Raquel Chicharro This course consists of three components: Lectures Exercises Seminar [Wed., 2-4] [Thu., 4-5]
More informationPayne-Scott workshop on Hyper Compact HII regions Sydney, September 8, 2010
Payne-Scott workshop on Hyper Compact HII regions Sydney, September 8, 2010 Aim Review the characteristics of regions of ionized gas within young massive star forming regions. Will focus the discussion
More informationTheoretical ideas About Galaxy Wide Star Formation! Star Formation Efficiency!
Theoretical ideas About Galaxy Wide Star Formation Theoretical predictions are that galaxy formation is most efficient near a mass of 10 12 M based on analyses of supernova feedback and gas cooling times
More informationIonized Hydrogen (HII)
Ionized Hydrogen (HII) While ionized hydrogen (protons, electrons) forms the majority of the ionized phase of the ISM, it also contains ionized forms of other elements: e.g., OII, OIII, CIV, MgII. Highest
More informationCHAPTER 22. Astrophysical Gases
CHAPTER 22 Astrophysical Gases Most of the baryonic matter in the Universe is in a gaseous state, made up of 75% Hydrogen (H), 25% Helium (He) and only small amounts of other elements (called metals ).
More informationa few more introductory subjects : equilib. vs non-equil. ISM sources and sinks : matter replenishment, and exhaustion Galactic Energetics
Today : a few more introductory subjects : equilib. vs non-equil. ISM sources and sinks : matter replenishment, and exhaustion Galactic Energetics photo-ionization of HII assoc. w/ OB stars ionization
More informationThe Interstellar Medium (ch. 18)
The Interstellar Medium (ch. 18) The interstellar medium (ISM) is all the gas (and about 1% dust) that fills our Galaxy and others. It is the raw material from which stars form, and into which stars eject
More informationAstrophysics of Gaseous Nebulae and Active Galactic Nuclei
SECOND EDITION Astrophysics of Gaseous Nebulae and Active Galactic Nuclei Donald E. Osterbrock Lick Observatory, University of California, Santa Cruz Gary J. Ferland Department of Physics and Astronomy,
More informationEnergy Sources of the Far IR Emission of M33
Energy Sources of the Far IR Emission of M33 Hinz, Reike et al., ApJ 154: S259 265 (2004). Presented by James Ledoux 24 µm 70 µm 160 µm Slide 1 M33 Properties Distance 840kpc = 2.7 Mlyr (1'' ~ 4 pc) Also
More information80 2 Observational Cosmology L and the mean energy
80 2 Observational Cosmology fluctuations, short-wavelength modes have amplitudes that are suppressed because these modes oscillated as acoustic waves during the radiation epoch whereas the amplitude of
More informationAstrophysics of Gaseous Nebulae
Astrophysics of Gaseous Nebulae Astrophysics of Gaseous Nebulae Bright Nebulae of M33 Ken Crawford (Rancho Del Sol Observatory) Potsdam University Dr. Lidia Oskinova lida@astro.physik.uni-potsdam.de HST
More informationAST242 LECTURE NOTES PART 7
AST242 LECTURE NOTES PART 7 Contents 1. HII regions and Ionization Fronts 1 1.1. The Strömgren Sphere 2 1.2. Early Evolution 3 1.3. Achieving Pressure equilibrium 3 1.4. Jump conditions on an ionization
More informationReminders! Observing Projects: Both due Monday. They will NOT be accepted late!!!
Reminders! Website: http://starsarestellar.blogspot.com/ Lectures 1-15 are available for download as study aids. Reading: You should have Chapters 1-14 read. Read Chapters 15-17 by the end of the week.
More informationChapter 19: Our Galaxy
Chapter 19 Lecture Chapter 19: Our Galaxy Our Galaxy 19.1 The Milky Way Revealed Our goals for learning: What does our galaxy look like? How do stars orbit in our galaxy? What does our galaxy look like?
More informationASTRO 310: Galac/c & Extragalac/c Astronomy Prof. Jeff Kenney. Class 7 Sept 19, 2018 The Milky Way Galaxy: Gas: HII Regions
ASTRO 310: Galac/c & Extragalac/c Astronomy Prof. Jeff Kenney Class 7 Sept 19, 2018 The Milky Way Galaxy: Gas: HII Regions importance of HII regions one of main ISM phases great example for understanding
More informationStellar Life Cycle in Giant Galactic Nebula NGC 3603
Stellar Life Cycle in Giant Galactic Nebula NGC 3603 edited by David L. Alles Western Washington University e-mail: alles@biol.wwu.edu Last Updated 2009-11-20 Note: In PDF format most of the images in
More information18. Stellar Birth. Initiation of Star Formation. The Orion Nebula: A Close-Up View. Interstellar Gas & Dust in Our Galaxy
18. Stellar Birth Star observations & theories aid understanding Interstellar gas & dust in our galaxy Protostars form in cold, dark nebulae Protostars evolve into main-sequence stars Protostars both gain
More informationRadiation processes and mechanisms in astrophysics I. R Subrahmanyan Notes on ATA lectures at UWA, Perth 18 May 2009
Radiation processes and mechanisms in astrophysics I R Subrahmanyan Notes on ATA lectures at UWA, Perth 18 May 009 Light of the night sky We learn of the universe around us from EM radiation, neutrinos,
More informationAstr 5465 March 6, 2018 Abundances in Late-type Galaxies Spectra of HII Regions Offer a High-Precision Means for Measuring Abundance (of Gas)
Astr 5465 March 6, 2018 Abundances in Late-type Galaxies Spectra of HII Regions Offer a High-Precision Means for Measuring Abundance (of Gas) Emission lines arise from permitted (recombination) and forbidden
More informationNotes on Photoionized Regions Wednesday, January 12, 2011
Notes on Photoionized Regions Wednesday, January 12, 2011 CONTENTS: 1. Introduction 2. Hydrogen Nebulae A. Ionization equations B. Recombination coefficients and cross sections C. Structure of the hydrogen
More informationDark Matter ASTR 2120 Sarazin. Bullet Cluster of Galaxies - Dark Matter Lab
Dark Matter ASTR 2120 Sarazin Bullet Cluster of Galaxies - Dark Matter Lab Mergers: Test of Dark Matter vs. Modified Gravity Gas behind DM Galaxies DM = location of gravity Gas = location of most baryons
More informationAstr 2320 Thurs. April 27, 2017 Today s Topics. Chapter 21: Active Galaxies and Quasars
Astr 2320 Thurs. April 27, 2017 Today s Topics Chapter 21: Active Galaxies and Quasars Emission Mechanisms Synchrotron Radiation Starburst Galaxies Active Galactic Nuclei Seyfert Galaxies BL Lac Galaxies
More informationPossible Extra Credit Option
Possible Extra Credit Option Attend an advanced seminar on Astrophysics or Astronomy held by the Physics and Astronomy department. There are seminars held every 2:00 pm, Thursday, Room 190, Physics & Astronomy
More informationLECTURE 1: Introduction to Galaxies. The Milky Way on a clear night
LECTURE 1: Introduction to Galaxies The Milky Way on a clear night VISIBLE COMPONENTS OF THE MILKY WAY Our Sun is located 28,000 light years (8.58 kiloparsecs from the center of our Galaxy) in the Orion
More informationPart 2. Hot gas halos and SMBHs in optically faint ellipticals. Part 3. After Chandra?
Hot gas and AGN Feedback in Nearby Groups and Galaxies Part 1. Cool cores and outbursts from supermassive black holes in clusters, groups and normal galaxies Part 2. Hot gas halos and SMBHs in optically
More informationThe Interstellar Medium
The Interstellar Medium Fall 2014 Lecturer: Dr. Paul van der Werf Oortgebouw 565, ext 5883 pvdwerf@strw.leidenuniv.nl Assistant: Kirstin Doney Huygenslaboratorium 528 doney@strw.leidenuniv.nl Class Schedule
More informationSupernova Feedback in Low and High Mass Galaxies: Luke Hovey 10 December 2009
Supernova Feedback in Low and High Mass Galaxies: Luke Hovey 10 December 2009 Galactic Winds: Mathews, W. et al. 1971 Effects of Supernovae on the Early Evolution of Galaxies: Larson, R. 1974 The origin
More informationChapter 9. The Formation and Structure of Stars
Chapter 9 The Formation and Structure of Stars The Interstellar Medium (ISM) The space between the stars is not completely empty, but filled with very dilute gas and dust, producing some of the most beautiful
More information23 Astrophysics 23.5 Ionization of the Interstellar Gas near a Star
23 Astrophysics 23.5 Ionization of the Interstellar Gas near a Star (8 units) No knowledge of Astrophysics is assumed or required: all relevant equations are defined and explained in the project itself.
More informationAy Fall 2004 Lecture 6 (given by Tony Travouillon)
Ay 122 - Fall 2004 Lecture 6 (given by Tony Travouillon) Stellar atmospheres, classification of stellar spectra (Many slides c/o Phil Armitage) Formation of spectral lines: 1.excitation Two key questions:
More informationChapter 15 The Milky Way Galaxy. The Milky Way
Chapter 15 The Milky Way Galaxy The Milky Way Almost everything we see in the night sky belongs to the Milky Way We see most of the Milky Way as a faint band of light across the sky From the outside, our
More informationChapter 11 The Formation of Stars
Chapter 11 The Formation of Stars A World of Dust The space between the stars is not completely empty, but filled with very dilute gas and dust, producing some of the most beautiful objects in the sky.
More informationOur goals for learning: 2014 Pearson Education, Inc. We see our galaxy edge-on. Primary features: disk, bulge, halo, globular clusters All-Sky View
Our Galaxy Chapter 19 Lecture The Cosmic Perspective 19.1 The Milky Way Revealed What does our galaxy look like? What does our galaxy look like? How do stars orbit in our galaxy? Seventh Edition Our Galaxy
More informationStellar atmospheres: an overview
Stellar atmospheres: an overview Core M = 2x10 33 g R = 7x10 10 cm 50 M o 20 R o L = 4x10 33 erg/s 10 6 L o 10 4 (PN) 10 6 (HII) 10 12 (QSO) L o Photosphere Envelope Chromosphere/Corona R = 200 km ~ 3x10
More informationM.Phys., M.Math.Phys., M.Sc. MTP Radiative Processes in Astrophysics and High-Energy Astrophysics
M.Phys., M.Math.Phys., M.Sc. MTP Radiative Processes in Astrophysics and High-Energy Astrophysics Professor Garret Cotter garret.cotter@physics.ox.ac.uk Office 756 in the DWB & Exeter College Radiative
More informationThe Hot Gaseous Halos of Spiral Galaxies. Joel Bregman, Matthew Miller, Edmund Hodges Kluck, Michael Anderson, XinyuDai
The Hot Gaseous Halos of Spiral Galaxies Joel Bregman, Matthew Miller, Edmund Hodges Kluck, Michael Anderson, XinyuDai Hot Galaxy Halos and Missing Baryons Dai et al. (2010) Rich clusters have nearly all
More informationGalaxies and the Universe. Our Galaxy - The Milky Way The Interstellar Medium
Galaxies and the Universe Our Galaxy - The Milky Way The Interstellar Medium Our view of the Milky Way The Radio Sky COBE Image of our Galaxy The Milky Way Galaxy - The Galaxy By Visual Observation
More informationPart 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 informationThe Night Sky. The Universe. The Celestial Sphere. Stars. Chapter 14
The Night Sky The Universe Chapter 14 Homework: All the multiple choice questions in Applying the Concepts and Group A questions in Parallel Exercises. Celestial observation dates to ancient civilizations
More informationThe FIR-Radio Correlation & Implications for GLAST Observations of Starburst Galaxies Eliot Quataert (UC Berkeley)
The FIR-Radio Correlation & Implications for GLAST Observations of Starburst Galaxies Eliot Quataert (UC Berkeley) w/ Todd Thompson & Eli Waxman Thompson, Quataert, & Waxman 2007, ApJ, 654, 219 Thompson,
More informationStellar Life Cycle in Giant Galactic Nebula NGC edited by David L. Alles Western Washington University
Stellar Life Cycle in Giant Galactic Nebula NGC 3603 edited by David L. Alles Western Washington University e-mail: alles@biol.wwu.edu Introduction NGC 3603 is a giant HII region in the Carina spiral arm
More informationStars + Galaxies: Back of the Envelope Properties. David Spergel
Stars + Galaxies: Back of the Envelope Properties David Spergel Free-fall time (1) r = GM r 2 (2) r t = GM 2 r 2 (3) t free fall r3 GM 1 Gρ Free-fall time for neutron star is milliseconds (characteristic
More informationThe Milky Way - Chapter 23
The Milky Way - Chapter 23 The Milky Way Galaxy A galaxy: huge collection of stars (10 7-10 13 ) and interstellar matter (gas & dust). Held together by gravity. Much bigger than any star cluster we have
More informationA World of Dust. Bare-Eye Nebula: Orion. Interstellar Medium
Interstellar Medium Physics 113 Goderya Chapter(s): 10 Learning Outcomes: A World of Dust The space between the stars is not completely empty, but filled with very dilute gas and dust, producing some of
More informationVisible Matter. References: Ryden, Introduction to Cosmology - Par. 8.1 Liddle, Introduction to Modern Cosmology - Par. 9.1
COSMOLOGY PHYS 30392 DENSITY OF THE UNIVERSE Part I Giampaolo Pisano - Jodrell Bank Centre for Astrophysics The University of Manchester - March 2013 http://www.jb.man.ac.uk/~gp/ giampaolo.pisano@manchester.ac.uk
More informationASTR 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 informationAtomic Structure & Radiative Transitions
Atomic Structure & Radiative Transitions electron kinetic energy nucleus-electron interaction electron-electron interaction Remember the meaning of spherical harmonics Y l, m (θ, ϕ) n specifies the
More informationMolecular clouds (see review in astro-ph/990382) (also CO [12.1,12.2])
Molecular clouds (see review in astro-ph/990382) (also CO [12.1,12.2]) Massive interstellar gas clouds Up to ~10 5 M 100 s of LY in diameter. Giant Molecular Clouds (GMCs) defined to be M > 10 4 M High
More informationLecture 23 Internal Structure of Molecular Clouds
Lecture 23 Internal Structure of Molecular Clouds 1. Location of the Molecular Gas 2. The Atomic Hydrogen Content 3. Formation of Clouds 4. Clouds, Clumps and Cores 5. Observing Molecular Cloud Cores References
More informationView 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 informationThermal Bremsstrahlung
Thermal Bremsstrahlung ''Radiation due to the acceleration of a charge in the Coulomb field of another charge is called bremsstrahlung or free-free emission A full understanding of the process requires
More informationII. HII Regions (Ionization State)
1 AY230-HIIReg II. HII Regions (Ionization State) A. Motivations Theoretical: HII regions are intamitely linked with past, current and future starforming regions in galaxies. To build theories of star-formation
More informationTEMA 6. Continuum Emission
TEMA 6. Continuum Emission AGN Dr. Juan Pablo Torres-Papaqui Departamento de Astronomía Universidad de Guanajuato DA-UG (México) papaqui@astro.ugto.mx División de Ciencias Naturales y Exactas, Campus Guanajuato,
More informationAstronomy 1 Fall 2016
Astronomy 1 Fall 2016 Lecture11; November 1, 2016 Previously on Astro-1 Introduction to stars Measuring distances Inverse square law: luminosity vs brightness Colors and spectral types, the H-R diagram
More informationINTRODUCTION TO SPACE
INTRODUCTION TO SPACE 25.3.2019 The Galaxy II: Stars: Classification and evolution Various types of stars Interstellar matter: dust, gas Dark matter ELEC-E4530 Radio astronomy: the Sun, pulsars, microquasars,
More informationLecture 9. Quasars, Active Galaxies and AGN
Lecture 9 Quasars, Active Galaxies and AGN Quasars look like stars but have huge redshifts. object with a spectrum much like a dim star highly red-shifted enormous recessional velocity huge distance (Hubble
More information