SOFIA Quick Guide Instrument Capabilities & Science Cases
Table of Contents SOFIA Quick Guide Instrument Capabilities & Science Cases Table of Contents Overview...3 SOFIA Instruments EXES...4 FIFI-LS...6 FLITECAM...8 FORCAST... 10 FPI+... 12 GREAT... 14 HAWC+... 16 HIRMES... 18 Proposal Resources... 19 Further Information Instrument Pages www.sofia.usra.edu/science/instruments Observer s Handbook www.sofia.usra.edu/science/proposing-and-observing/sofia-observers-handbook-cycle-6 SOFIA Help Desk sofia_help@sofia.usra.edu Third printing; January 1, 2018 2
Overview The Stratospheric Observatory for Infrared Astronomy (SOFIA) is an airborne observatory consisting of a 2.5-meter effective diameter reflecting telescope, mounted onboard an extensively modified Boeing 747SP aircraft. A suite of instruments are available for imaging, spectroscopic, and polarimetric observations. This Quick Guide provides the technical specifications for each available instrument, along with examples of astronomical observations obtained with each. Details about the instruments and proposing for and observing with SOFIA may be found online as referenced on the previous page under Further Information. The SOFIA Instruments 3
EXES EXES: Echelon-Cross-Echelle Spectrograph Principal Investigator Class, High Res, Mid-Infrared Spectrograph Principal Investigator: Matthew J. Richter, University of California Davis Jupiter Spectral Maps The first EXES commissioning flight yielded spectral maps of Jupiter in two H 2 emission lines at 17.03 (S(1), ortho-h 2 ) and 28.22 μm (S(0), para-h 2 ). The ortho- to para-h 2 ratio is a measure of the temperature history and vertical motions in the atmosphere of Jupiter. The high-resolution (R~55,000) EXES spectral maps reveal limb brightened H 2 emission from the stratosphere of the planet. (EXES Team, P.I. Richter) Spectrally Resolved H 2 O Absorption Lines S(1) Continuum S(0) Continuum On its second commissioning flight, EXES generated a high resolution spectrum (R=80,000, 4 km/s) revealing gas phase H 2 O lines toward the massive Young Stellar Object AFGL 2591. Shown in the figure below are the spectrum of AFGL 2591 (black trace), telluric standard (red trace), and the residual after telluric and baseline correction (top). The transition near 6.115 μm is that of absorption by para-h 2 O in the ground state, Doppler shifted by ~40 km/s from the deep telluric feature at the time of the observations. The EXES observations Arcsec Arcsec resolve the H 2 O lines for the first time. The line width of 15 km/s locates the gas at the base of the molecular outflow. (Indriolo et al., 2015, ApJL, 802, 14.) AFGL 2591 Spectrum Arcsec Arcsec Arcsec S(1) Jupiter Spectral Maps Arcsec S(0) Intensity (Arbitrary Units) 4
Specifications High resolution is provided by an echelon (a coarsely-ruled, steeply-blazed, aluminum reflection grating) along with an echelle grating to cross-disperse the spectrum. The echelon can be bypassed so that the echelle acts as the sole dispersive element, resulting in single order spectra at medium or low resolution depending on the incident angle. The available configurations are Low (low resolution), Medium (medium resolution), HIGH_MED, and HIGH_LOW. Configurations are called HIGH_MED if the cross disperser echelle angle is 35-65 and HIGH_LOW for angles between 10-25. The shorter slits in HIGH_LOW allow for more orders to be packed onto the array, thus increasing the instantaneous wavelength coverage while maintaining the high spectral resolution. Single Setting Spectral Coverage (µm) Spectral Coverage Low (and HIGH_LOW) configuration HIGH_MED orders larger than detector for λ > 19 µm causes increasing gaps in coverage Medium (and HIGH_MED) configuration Source Flux Density Required (Jy) Extended Object Brightness (Jy / sq arcsec) High Resolution Above: Sensitivities for point (top) and extended (bottom) sources, assuming nominal conditions. Spectral Parameters Configuration Slit Length Spectral Resolution Low 1,000 3,000 25 180 Medium 5,000 20,000 HIGH_MED 1.5 45 HIGH_LOW 1 12 50,000 100,000 In the Medium and Low configurations the slit lengths vary from 25 to 180 depending on the number of rows to be read. HIGH_MED Configuration HIGH_LOW Configuration Left: Raw 2D spectra without nod-subtraction to highlight the sky emission lines (dark). Possessing the same spectral resolution, HIGH_LOW has a larger spectral coverage at the expense of a shorter slit. 5
FIFI-LS FIFI-LS: Field Imaging Far-Infrared Line Spectrometer Facility Class, Integral Field, Far-Infrared Spectrometer Principal Investigator: Alfred Krabbe, German SOFIA Institute, University of Stuttgart Cat s Eye Nebula: [OIII] 52 µm The FIFI-LS [O III] 52 μm spectral map of the Planetary Nebula NGC 6543 (the Cat s Eye Nebula) traces the location of the ionized gas. Shifts in the central wavelength correspond to velocity gradients that are present across the nebula. Each pixel in the 5x5 map corresponds to about 6000 AU at the ~1 kpc distance of NGC 6543. The FIFI-LS field of view is shown superimposed on an image obtained with the Nordic Optical Telescope. (FIFI-LS Team) Intensity FIFI-LS [OIII] 52 µm Wavelength y x NGC 6543 Spectral Map [N II] λ6584å [O III] λ5007å [O III] λ5007å FIFI-LS Team, R.L.M. Corradi, Isaac Newton Group, and D. Goncalves, Instituto de Astrofísica de Canarias. Orion Nebula: [OI] 146 µm The Orion Nebula was mapped by FIFI-LS at 146 µm to study the physical conditions of its atomic and molecular gas. The far infrared continuum (logarithmic scale) is shown peaking at the Becklin-Neugebauer object, but also clearly shows the Orion Bar and a similar structure to the north-east (left). Additionally, the [OI] line emission tracing the photon-dominated regions around the Trapezium stars where the star s UV radiation irradiates the surrounding molecular cloud (right). (FIFI-LS Team) arcminutes M42 [OI] 146 µm Continuum Orion Bar Becklin- Neugebauer Object arcminutes M42 [OI] 146 µm Emission Orion Bar Becklin- Neugebauer Object 6
Specifications FIFI-LS is an integral field, far-infrared spectrometer consisting of two independent grating spectrometers. Each spectrometer has a detector consisting of 400 pixels of Gallium-doped Germanium photoconductors. The projection onto the sky of the 5x5-pixel FOVs of the blue channel and the red channel is nearly concentric (10 offset), but the angular coverage differs. The spectral resolution channels vary between 500 and 2000, depending on the observed wavelength, with higher values reached towards the long wavelength ends of each spectrometer. Sensitivity values calculated for a SNR of 4 in 900 s MDLF (10-17 wm -2 ) Minimum Detectable Line Flux Short Channel; Order 2 Short Channel; Order 1 Long Channel Minimum Detectable Continuum Flux Channel Parameters Channel Field of View Pixel Size λ Range Blue 30 x 30 6 x 6 51 120 µm Red 1 x 1 12 x 12 115 203 µm MDCF (Jy) Short Channel; Order 2 Short Channel; Order 1 Long Channel spectrograph slit spectral dimension spatial dimension 16 x 25 pixel detector array Data Cube 12 x 12 (110 210 µm) 5 x 5 pixels 1 focal plane 6 x 6 (42 110 µm) spectral dimension spatial dimension 16 x 25 pixel detector array spectrograph slit Left: The integral field unit for each channel consists of 15 specialized mirrors to slice the two dimensional 5x5 pixel FOV into five slices that are each five pixels long, which are then reorganized along a one dimensional line (25x1 pixel), forming the spectrometer entrance slit. The diffraction grating disperses the incoming light, which reaches the 16x25 pixel detector array. The result is a data cube with 5x5 spatial pixels and 16 pixels in the spectral dimension. Instantaneous Spectral Coverage Spectral Resolution Velocity Width (km s -1 ) Long Channel Short Channel; Order 1 Short Channel; Order 2 Velocity Resolution (km s -1 ) Short Channel; Order 2 Short Channel; Order 1 Long Channel Spectral Resolution (λ/δ λ) 7
FLITECAM FLITECAM: First Light Infrared Test Experiment CAMera Facility Class, Near-Infrared Camera and Spectrograph Principal Investigator: Ian McLean, University of California Los Angeles SN 2014J Entire Feature Profile FLITECAM observed the H + K-band spectrum on Feb. 19, 2014 and Feb. 27, 2014 with strong emission features at 1.55-1.65 μm and 1.77 μm. The detail of the geometry of the 1.77 μm emission peak has enabled it to be identified as permitted lines of Co ΙΙ rather than a blend of Fe group lines and Co ΙΙ as previously believed. The strongest emission lines of Co ΙΙ and [Co ΙΙΙ] are presented in the bottom of each plot, and triangles indicate the locations of lines predicted to be strong in the model for comparison. Flux (10-13 w/m 2 /µm) [Co III] Co II SN 2014J Spectrum Favorable atmospheric transmission achievable in the stratosphere onboard SOFIA has enabled FLITECAM spectra to be the only data collected on SN 2014J that spans the entire feature profile. (Vacca, W. D. et al., 2015, ApJ, 804, 66.) [Co III] Co II NGC 7023 at 3.3 µm PAH Filter Observation at 3.3 µm A 3.3 μm polycyclic aromatic hydrocarbon (PAH) filter was used to study the photochemical evolution of PAHs in the reflection nebula NGC 7023. The filter is narrow, λ=0.09 μm, and isolates the PAH emission. The plate scale is 0.475 arcsec/pixel and the angular resolution is about 2 arcsec, dominated by telescope jitter. FORCAST also performed observations of NGC 7023 (at 11.2 μm) and the combined data shows a peak in the 11.2/3.3 μm ratio, corresponding to PAHs of ~50 C-atoms. This supports models claiming the photochemical evolution of PAHs is size-dependent and most efficient for PAHs with ~50 C-atoms. (Croiset et al. 2016, A&A, 590, A26.) Dec (J2000) 8
Specifications Imaging FLITECAM consists of a cryogenically cooled near-infrared camera operating and using refractive optics with the specifications below. MDCF (mjy) Spectroscopy Detector Information Field of View Detector Array λ Range ~8 diameter 1024x1024 InSb 0.475 x 0.475 pixels FLITECAM Imaging Sensitivity FLITECAM FLITECAM co-mounted with HIPO 1.0 5.5 µm The instrument has a set of broadband filters for imaging (top right), as well as grisms for moderate-resolution spectroscopy (below). Atmospheric Transmission Cycle 4 theoretical continuum point source sensitivities for a S/N of 4 in 900 s at partial water vapor (PWV) overburdens of 7 μm. The horizontal bars correspond to the photometric band pass. Passband Filter Parameters λ eff (µm) Standard Filters 5%BW a (µm) J 1.24 0.29 H 1.63 0.31 K 2.10 0.40 L 3.53 0.65 L 3.86 0.70 Specialty Filters Pa α 1.87 0.03 Pa α Cont. 1.90 0.03 H 2 O Ice 3.05 0.19 PAH 3.30 0.12 L narrow 3.61 0.23 M narrow 4.80 0.19 Order Sorting Filters H wide 1.79 0.59 K wide 2.30 0.88 K long 2.45 0.55 L+M 4.11 2.72 a Bandwidth for transmission level is >5%. Grism A B C Order Sorting Filters Grism Characteristics Coverage (µm) R (λ/δλ) Highres Lowres L+M 4.40 5.53 K long 2.27 2.72 1690 1140 H wide 1.55 1.83 1710 1290 L+M 3.30 4.07 1780 1200 H wide 1.68 2.05 1750 1320 J 1.14 1.39 1720 1425 L+M 2.78 3.40 1670 1300 K wide 1.91 2.28 1650 1390 H 1.50 1.72 1640 1400 MDCF (Jy) Grism Sensitivities FLITECAM (green) and FLITECAM+HIPO (blue) grism continuum point source sensitivities across FLITECAM bandpasses. 9
FORCAST FORCAST: Faint Object InfraRed Camera for the SOFIA Telescope Facility Class, Mid/Far-Infrared Camera and Spectrograph Principal Investigator: Terry Herter, Cornell University NGC 7023 FORCAST 11.1 µm Filter FORCAST+FLITECAM+Spitzer/IRAC PAH Tracing at 11.2 µm FORCAST has been used to collect 11.1 µm data of NGC 7023 (top left) which was then combined with FLITECAM 3.3 µm data and Spitzer/IRAC 8.0 µm data (top right) to yield a plot of the 11.2/3.3 µm flux ratio revealing the PAH size distribution (bottom). FORCAST observations provide higher angular resolution than Spitzer which thereby enables the PAH size distribution to be traced through the ratio of 11.2 µm emission to the SOFIA/FLITECAM 3.3 µm data. The famous reflection nebula NGC 7023 was observed with FORCAST in order to better understand the photochemical evolution of polycyclic aromatic hydrocarbons (PAHs) resulting from illumination by the nearby star HD 200775. Similarities to the H 2 flux (contours) indicate that the smallest PAH molecules lie on the surface of the PDR. (Croiset et al. 2016, A&A, 590, A26.) Dec (J2000) Dec (J2000) RA (J2000) 11.2 / 3.3 µm HD 200775 Grism Coverage from 5 37 µm V339 Delphini The early temporal development of the classical nova V339 Delphini was observed using FORCAST grisms, which provide coverage from 5 40 µm at low spectral resolution. These data revealed a full suite of hydrogen recombination lines, the analysis of which indicated that the ejecta were still at very high density (n e > 10 13 cm -3 ) and that the hydrogen lines were optically thick. (Gehrz et al. 2015, ApJ, 812, 132.) Flux (Jy) 10
Specifications The short wavelength channel (SWC) and long wavelength channel (LWC) can be used individually or together for simultaneous imaging of the same field of view. Imaging The point spread function (PSF) in FORCAST images is consistent with the telescope s diffraction limit convolved with the 1.3 rms jitter. In dual channel mode, a dichroic is used to split the beam into the SWC and LWC, decreasing the throughput of the system by 40-85% relative to the single channel mode. MDCF (mjy) FORCAST Sensitivity Single Channel Dual Channel (Dichroic) Cycle 6 continuum point source sensitivities for single and dual channel modes. Values are for S/N = 4 in 900 s under nominal conditions. Investigators are encouraged to use the SOFIA Integration Time Calculator (SITE) for their calculations. Camera Details Camera Wavelength Range Detector SWC 5 25 µm Si:As (BIB) LWC 25 40µm Si:Sb (BIB) Each channel consists of a 256x256 pixel array that yields a 3.4 x3.2 instantaneous field-of-view with 0.768 pixels λ eff (µm) SWC Filters Filter Parameters Δλ (µm) λ eff (µm) LWC Filters Δλ (µm) 5.4 0.16 24.2 2.9 5.6 0.08 31.5 5.7 6.4 0.14 33.6 1.9 6.6 0.24 34.8 3.8 7.7 0.47 37.1 3.3 8.8 0.41 11.1 0.95 11.2 2.7 11.3 0.24 11.8 0.74 19.7 5.5 25.4 1.86 A subset of these will be chosen each cycle as the nominal set. Spectroscopy FORCAST grisms provide coverage from 5 40 μm. Blazed diffraction gratings are used in transmission and stacked with blocking filters to prevent order contamination. Two long slits (2.4 x191, 4.7 x191 ) are available. Grism Details Grism Coverage (µm) R (λ/δλ) a G063 4.9 8.0 120 c /180 G111 8.4 13.7 130 c /260 G227 17.6 27.7 110/120 G329 28.7 37.1 160/170 b a For the 4.7 x191 and the 2.4 x191 slits, respectively. b Not available during Cycle 6. c The resolution of the long, narrow-slit modes is dependent on (and varies slightly with) the in-flight IQ. MDCF (Jy) FORCAST Grism Sensitivities Cycle 6 grism continuum point source sensitivities for both wide and narrow long slits overlaid on an atmospheric transmission model (light blue). Values are for S/N = 4 in 900 s under nominal conditions. Atmospheric Transmission 11
FPI+ FPI+: Focal Plane Imager Plus Fast Frame Rate Optical Photometer Principal Investigator: Jürgen Wolf, DSI Pluto Stellar Occultation The 2015 stellar occultation by Pluto of a background star with an r-band of magnitude ~12 was captured by FPI+ as a light curve, showing the decreased signal (in magnitudes) during the event. The central flash in the middle of the light curve confirms the precise position of SOFIA on the centerline of the shadow path, allowing for analysis of the upper atmosphere. This results in a best-fit value for the occultation half-light radius of 1288±1 km (i.e., the radius in the atmosphere at which the occultation light curve drops to half its original flux due to refraction). (Bosh et al. 2016, submitted.) Normalized Differential Magnitude Stellar Occultation by Pluto 2015-06-29 SOFIA FPI+ Data Geocentric Julian Date (UTC) 2457203 C2013 US10 Catalina Coma FPI+ produced an Ι-band image of Comet C2013 US10 Catalina as part of a combined infrared and visual observation. The comet s coma is nicely visible in comparison to the more compact stars toward the bottom of the image. (C.E. Woodward et al.) I-band Image of Comet C2013 US10 Catalina 12
Specifications FPI+ is the upgrade to FPI with a science grade CCD sensor. More than 50% of the light detected onboard SOFIA between 480 nm and 800 nm is transmitted to FPI+, the range at which the camera is most sensitive. The CCD sensor is an e2v CCD 201-20 1024x1024 pixel frame transfer EMCCD with the specifications given in the Optical Properties table (right). Six spectral filters are available, including five Sloan Digital Sky Survey filters u, g, r, i, z and a Schott RG1000 near-ir cut-on (Daylight) filter. At the wavelengths where the Sloan u filter is transparent, other elements in the FPI+ light path are nearly opaque, resulting in a very low throughput (~0.5%). There are an additional three neutral density (ND) filters that can be used to attenuate bright stars. The filters are installed in a double-carousel filter wheel with six positions in each carousel, a list of which is given in the Filter Suite table (right). Filters from Carousel 1 and Carousel 2 can be combined freely with a few exceptions. Optical Properties Field of View λ Range Plate Scale 8.7 x 8.7 360 1100 nm 0.51 per period Filter Suite Carousel 1 Carousel 2 OPEN OPEN Sloan u ND 1 Sloan g ND 2 Sloan r ND 3 Sloan i Daylight Sloan z Blocked Filter Throughput Sensitivity Optical Efficiency Exposure Time (s) SNR = 5 SNR = 10 SNR = 20 λ (µm) Plot of the optical efficiency for five spectral filters and the OPEN FPI+ configuration. The plot includes the calculated SOFIA telescope throughput, the instrument quantum efficiency, and the measured filter spectral response. Stellar Magnitudes (V mag) Required Exposure Time in OPEN filter configuration for Signal to Noise values of SNR = 5, 10, and 20. These low SNR values are sufficient to detect a stellar occultation. 13
GREAT GREAT: German REceiver for Astronomy at Terahertz Frequencies Principal Investigator Class, Far-Infrared, Multi-Pixel Spectrometer Principal Investigator: Dr. Rolf Güsten, MPifR, Bonn Horsehead Nebula Velocity Resolved Map A velocity resolved map of the iconic Horsehead Nebula in the [C II] 158 μm line was obtained by the upgreat Low Frequency Array (LFA). The [CII] line is one of the strongest cooling lines in the interstellar medium, and here it traces the photodissociation region illuminated by the O9.5V star Sigma Orionis. The integrated intensity image is shown in the figure to the right. The 12 x17 map, encompassing the nebula and the underlying cloud ridge, was obtained in just over 4 hours of observation on a single flight. The angular resolution of the map is 15.1 and the velocity resolution is 0.19 km/s (R > 10 6 ). These remarkably efficient observations were made possible by an increase in the sensitivity of the upgreat detectors with the use of fourteen independent detectors of the LFA, and the increased mapping speed facilitated by SOFIA s inertially stable platform. Horsehead C+ Emission Integrated Velocity Range from 9.5 to 11.5 km/s Dec (J2000) RA (J2000) Data publicly available in the SOFIA Science Archive. T mb kms -1 (K kms -1 ) Planetary Nebula NGC 7027 NGC 7027 Spectrum GREAT [OΙ] 63 μm NGC 7027 Spatial scans made by the GREAT spectrometer s H-channel receiver enabled the production of a spectral map and integrated spectrum for Planetary Nebula NGC Velocity (km/s) 7027 in the [OI] 63 μm line. The effective angular resolution is indicated by the gray circle. The high resolution spectrum displays the characteristic shape for an expanding, optically thin shell. The complex line structure shows that the expanding nebula has multiple components moving at different velocities. (GREAT Consortium) NGC 7027 Spectral Map RA Offset (arcsec) Dec Offset (arcsec) 14
Specifications GREAT supports the following Astronomical Observing Templates: Single Point, Raster map, and On the Fly map. Each AOT is run in either of two observing modes: Total Power or Beam Switching. Observing Modes Total Power: The telescope moves between a target and a nearby emission-free reference position. Beam Switching: The secondary mirror chops between the source and a nearby reference position at a rate of ~1 2.5 Hz. The telescope nods between these positions at a slower rate than when chopping. LFA & HFA Pixel Arrays A generalized hexagonal pattern of the LFA and HFA. The spacing between pixels, r, is slightly more than two beam widths at ~31.7 for LFA and 13.8 for HFA. Astronomical Observing Templates Single Point: The telescope observes a single point on the sky to acheive long integration times. Raster Map: The telescope makes a collection of single point observations to cover a small mapping area. On The Fly Map: The telescope scans along a row while backends* continuously integrate the incoming signal and periodically write out the data. This process continues to develop a map of the desired size. *Both GREAT and the upgreat LFA use Fast Fourier Transform backends with a bandwidth of ~2.5 GHz and a channel spacing of 44 khz. At the [CII] frequency (1.9 THz), this corresponds to a channel spacing of ~0.01 km/s. upgreat and 4GREAT upgreat and 4GREAT are enhancements to GREAT. The upgreat Low Frequency Array (LFA) is a dual polarization, 2x7 pixel array operating at ~1.9 THz, and the upgreat High Frequency Array (HFA) is a 1x7 pixel array operating at 4.745 THz. In On the Fly mode, upgreat can observe extended regions of the sky efficiently, as shown by the Horsehead Nebula map on the previous page. 4GREAT has four single-pixel channels that observe the same position on the sky simultaneously. Their central frequencies are 0.43, 1.00, 1.37, and 2.54 THz. For Cycle 6, GREAT can be run with the configurations upgreat LFA with upgreat HFA or 4GREAT with upgreat HFA. Channels Frequency Range [THz] Channel Parameters T rec Double Sideband FWHM Astronomical Lines of Interest upgreat LFA 1.90 +/ 5 GHz 1000 K 15 [CII], CH, [OI](2-1), CO(16-15) upgreat HFA 4.745 1100 K 6 [OI] 4GREAT a 1.240 1.50 800 K 19 [NII], CO, OD, SH, H 2 D+ 2.490 2.590 1500 K 12 18 OH 2 Π 3/2 a Only the shown bands (3 and 4) are available for Cycle 6 observations. 15
HAWC+ HAWC+: High-resolution Airborne Wideband Camera Plus Facility Class, Far-Infrared Camera and Polarimeter Principal Investigator: C. Darren Dowell, Jet Propulsion Laboratory Star Forming Region W3 The structure of the far-infrared polarization in the W3 star forming region, as observed by HAWC+ at a wavelength of 89 μm. Each line segment represents the orientation of polarization at that location overlaid on an image of the total intensity at the same wavelength. Vectors represent the electric field direction. For clarity, only one-quarter of the polarization measurements are shown and the the line segments are set to a fixed length. The polarization is caused by the partially oriented radiation from elongated dust grains that are aligned with the magnetic field in the cloud. (HAWC+ Team) W3 Polarimetry Star Forming Region Orion HAWC+ performed polarization measurements at 89 μm to capture the structure of the magnetic field in the Orion star forming region. Each line segment represents the orientation of the magnetic field at that location, overlaid on an image of the total intensity at the same wavelength. The total intensity image has a pixel scale of 1.5 arcsec per pixel and the polarization results were smoothed to a scale of 8 arcsec per pixel to produce statistically independent vectors in this HAWC+ observing band. For clarity, the line segments are set to a fixed length. (HAWC+ Team) Orion Polarimetry 16
Specifications HAWC+ is designed to offer imaging and polarimetry in each of its five bands ranging from λ=53 to 214 μm. HAWC+ uses standard chopped-nodded observing patterns for polarimetry with a number of efficient scan modes for total intensity imaging observations. 64x40 HAWC+ Array Footprint Band/ Wavelength The polarization mode consists of a wire grid that reflects and transmits the incident light in two linear and orthogonal polarization states. This wire grid directs the two polarization components to two detectors providing an useful field of view (FOV) of 32x40 pixels. The detectors are designed to deliver background-limited performance with high quantum efficiency for all the HAWC+ continuum bands. Instrument Parameters for Bands A E Δλ Angular Resolution Total Intensity FOV (arcmin) Polarization FOV (arcmin) A / 53 µm 9.01 4.9 FWHM 2.8 x 1.7 1.4 x 1.7 B a / 63 µm 9.45 5.8 FWHM 4.2 x 2.7 2.1 x 2.7 C / 89 µm 16.91 7.8 FWHM 4.2 x 2.7 2.1 x 2.7 D / 154 µm 33.88 13.6 FWHM 7.4 x 4.6 3.7 x 4.6 Available footprint for total intensity observations using the 64x40 HAWC+ array in Band E. For polarization observations, only a 32x40 FOV is available and is half of the blue rectangle. E / 214 µm 42.8 18.2 FWHM 10.0 x 6.3 5.0 x 6.3 a Currently unavailable due to saturation in the band but may be offered as shared risk in future cycles. MDCF (mjy) HAWC+ Sensitivity Sensitivity estimates in units of the Minimum Detectable Continuum Flux (MDCF) into a single beam. Values take into account all expected overheads. For polarization, the plotted data show the polarized intensity p x I, where p is the fractional polarization. Predicted Performance for Continuum Imaging and Polarimetry Instrument Parameter Band A Band B Band C Band D Band E NESB a (MJy sr -1 h 1/2 ) 18.8 11.4 6.3 1.6 0.8 MDCF b (mjy) 175 199 148 115 101 Mapping Speed c 0.117 0.489 1.624 42.05 243 MDCPF d (Jy) 16.3 18.5 13.7 10.7 9.4 MIfP e (MJy sr -1 h 1/2 ) 27,828 16,942 9325 2406 1167 a Noise Equivalent Surface Brightness for S/N=1 into a single beam. b Minimum Detectable Continuum Flux for a point source with S/N=4 in 900s. c Real scan rate required to achieve a given NESB. Units: arcmin 2 h -1 (MJy sr -1 ) -2 d Minimum Detectable Continuum Polarized Flux for a point source with S/N=4 in 900s. e Minimum total Intensity required to measure Polarization to an uncertainty level σ p 0.3%. All chop/nod and polarization overhead values have been applied to this value. 17
HIRMES HIRMES: HIgh Resolution Mid-infrarEd Spectrometer Facility Class, High Res, Mid-Infrared Spectrometer Principal Investigator: Harvey Moseley, Goddard Space Flight Center, MD Protoplanetary Disk Physics HIRMES will aim to study the evolution of protoplanetary systems. Shocks resulting in ionized gas emission lines due to mass accretion lead to star and planet formation. Features of particular interest include water lines and ice, [OI] as a tracer of disk chemistry and radial structure, and HD as a tracer of disk mass. While Herschel and Spitzer focused on tracing intensity and spatial profiles, HIRMES will expand on this to yield spectral profiles by resolving these lines and determining their origins from velocity profiles, which are key components of shock models. Specifications Star 0 AU 0.1 AU 1.0 AU HIRMES employs background limited bolometers and a combination of Fabry-Perot interferometers and gratings. As a direct detection spectrometer, HIRMES has no inherent quantum noise limit. Furthermore, bolometers have >90% quantum efficiency over reasonably broad bands and lack generation recombination noise as compared to photoconductors (i.e. increased sensitivity). The Low, Mid, and Imaging Spectroscopy modes use a 16x64 MoAu TES bolometer pixel array and the High mode uses a 8x64 pixel array. The Imaging Spectroscopy mode has a wide field of view to enable large scale mapping of nearby galaxies in fine-structure line emission. Warm water vapor traced by 34.9 µm line Diffusive transport of water? λ Range Mode Disk mass traced by HD Oxygen traced by [OI] Snow line HIRMES is currently in development and is expected to begin observations in 2019. Observing Specs Spectroscopic Capabilities Ice/rock ratio traced by ice emission Formation of Icy Planetesimals Diffraction Limited 25 122 μm λ 30 μm Spectral Resolution Low 325 600 Mid ~ 12,000 High 50,000 100,000 Imaging Spectroscopy ~ 2,000 10 AU 100 AU 18
Proposal Resources Call for Proposals SOFIA s Call for Proposals (CfP) solicits observing proposals from the US and International astronomical communities. The CfP describes how to prepare and submit proposals, including details on how proposals will be evaluated, and formally establishes the policies for all matters concerned with the rules governing SOFIA operations for the current cycle. CfP for Cycle 6: www.sofia.usra.edu/sites/default/ files/other/documents/sofia_cy6_cfp.pdf Observer s Handbook The Observer s Handbook provides detailed information about the instruments that will be available for observations during the current cycle. This document is the primary technical reference for astronomers who wish to submit a proposal in response to the Call for Proposals. Observer s Handbook for Cycle 6: www.sofia. usra.edu/science/proposing-and-observing/sofiaobservers-handbook-cycle-6 Unified SOFIA Proposal and Observation Tool (USPOT) All proposals are to be prepared and submitted using the Unified SOFIA Proposal and Observation Tool (USPOT). Initial submission is completed during Phase I, and those proposals awarded observing time will be required to submit further specifications regarding their observations during Phase II all of which is completed via USPOT. USPOT: dcs.sofia.usra.edu/observationplanning/ installuspot/uspotdownload.jsp Exposure Time Estimation Calculators Estimations of exposure times for imaging with FLITECAM, FORCAST, FPI+, and HAWC+ can be made using the SOFIA Instrument Time Estimator (SITE), a web-based tool that provides total integration time or S/N for a given instrument, filter(s), source type (point, extended, emission line), and water vapor overburden. SITE: dcs.sofia.usra.edu/proposaldevelopment/site/ index.jsp Stand-alone Exposure Time Calculator (ETC) tools are available for the following: EXES: irastro.physics.ucdavis.edu/exes/etc/ FIFI-LS: atran.sofia.usra.edu/cgi-bin/fifi-ls/fifi.cgi FLITECAM Grism Observations: flitecam.sofia.usra. edu/cgi-bin/flitecam/flitecam_calc3.cgi FORCAST Grism Observations: forcast.sofia.usra. edu/cgi-bin/forcast/forcast_grisms_calc.cgi GREAT: great.sofia.usra.edu/cgi-bin/great/great.cgi Atmospheric Transmission (ATRAN) The atmospheric transmission as a function of wavelength may be obtained using the online tool ATRAN. The use of ATRAN is necessary for planning SOFIA high-resolution spectroscopic observations. ATRAN: atran.sofia.usra.edu/cgi-bin/atran/atran.cgi The USPOT Manual is designed to guide users through the procedures for submitting SOFIA Observing Proposals containing Astronomical Observation Requests (AORs). The USPOT Manual includes specific instructions for each instrument for both Phase I and Phase II. USPOT Manual: www.sofia.usra.edu/science/ proposing-and-observing/uspot-manual 19
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