Showing papers by "Michael W. Werner published in 2010"
TL;DR: In this article, the spectral properties of the fullerene C_(60) in the reflection nebula NGC 7023 were confirmed by detecting a third emission feature at 7.04 ± 0.05 μm.
Abstract: The fullerene C_(60) has four infrared-active vibrational transitions at 7.0, 8.5, 17.4, and 18.9 μm. We have previously observed emission features at 17.4 and 18.9 μm in the reflection nebula NGC 7023 and demonstrated spatial correlations suggestive of a common origin. We now confirm our earlier identification of these features with C_(60) by detecting a third emission feature at 7.04 ± 0.05 μm in NGC 7023. We also report the detection of these three C_(60) features in the reflection nebula NGC 2023. Our spectroscopic mapping of NGC 7023 shows that the 18.9 μm C_(60) feature peaks on the central star and that the 16.4 μm emission feature due to polycyclic aromatic hydrocarbons peaks between the star and a nearby photodissociation front. The observed features in NGC 7023 are consistent with emission from UV-excited gas-phase C_(60). We find that 0.1%-0.6% of interstellar carbon is in C_(60); this abundance is consistent with those from previous upper limits and possible fullerene detections in the interstellar medium (ISM). This is the first firm detection of neutral C_(60) in the ISM.
297 citations
TL;DR: In this article, the spectral properties of neutral C$60$ in the interstellar medium were confirmed by detecting a third emission feature at 7.04 $pm$ 0.05 $m in the reflection nebula NGC 7023.
Abstract: The fullerene C$_{60}$ has four infrared-active vibrational transitions at 7.0, 8.5, 17.4 and 18.9 $\mu$m. We have previously observed emission features at 17.4 and 18.9 $\mu$m in the reflection nebula NGC 7023 and demonstrated spatial correlations suggestive of a common origin. We now confirm our earlier identification of these features with C$_{60}$ by detecting a third emission feature at 7.04 $\pm$ 0.05 $\mu$m in NGC 7023. We also report the detection of these three C$_{60}$ features in the reflection nebula NGC 2023. Our spectroscopic mapping of NGC 7023 shows that the 18.9 $\mu$m C$_{60}$ feature peaks on the central star and that the 16.4 $\mu$m emission feature due to polycyclic aromatic hydrocarbons peaks between the star and a nearby photodissociation front. The observed features in NGC 7023 are consistent with emission from UV-excited gas-phase C$_{60}$. We find that 0.1-0.6% of interstellar carbon is in C$_{60}$; this abundance is consistent with those from previous upper limits and possible fullerene detections in the interstellar medium. This is the first firm detection of neutral C$_{60}$ in the interstellar medium.
290 citations
University of California, Berkeley1, National Radio Astronomy Observatory2, California Institute of Technology3, Tel Aviv University4, Royal Military College of Canada5, Pennsylvania State University6, Weizmann Institute of Science7, University of Toronto8, University of Hawaii9, Max Planck Society10, Harvard University11, Las Cumbres Observatory Global Telescope Network12, University of Virginia13, Goddard Space Flight Center14, Hebrew University of Jerusalem15
TL;DR: In this paper, the authors present multi-wavelength (radio through X-ray) observations of GRBs 050820A, 060418, and 080319B, and construct afterglow models to extract the opening angle and beaming-corrected energy release for all three events.
Abstract: Long-duration gamma-ray bursts (GRBs) are widely believed to be highly collimated explosions (bipolar conical outflows with half-opening angle θ ≈ 1°-10°). As a result of this beaming factor, the true energy release from a GRB is usually several orders of magnitude smaller than the observed isotropic value. Measuring this opening angle, typically inferred from an achromatic steepening in the afterglow light curve (a "jet" break), has proven exceedingly difficult in the Swift era. Here, we undertake a study of five of the brightest (in terms of the isotropic prompt γ-ray energy release, E_(γ,iso)) GRBs in the Swift era to search for jet breaks and hence constrain the collimation-corrected energy release. We present multi-wavelength (radio through X-ray) observations of GRBs 050820A, 060418, and 080319B, and construct afterglow models to extract the opening angle and beaming-corrected energy release for all three events. Together with results from previous analyses of GRBs 050904 and 070125, we find evidence for an achromatic jet break in all five events, strongly supporting the canonical picture of GRBs as collimated explosions. The most natural explanation for the lack of observed jet breaks from most Swift GRBs is therefore selection effects. However, the opening angles for the events in our sample are larger than would be expected if all GRBs had a canonical energy release of ~10^(51) erg. The total energy release we measure for the "hyper-energetic" (E_(tot) ≳ 10^(52) erg) events in our sample is large enough to start challenging models with a magnetar as the compact central remnant.
137 citations
University of Arizona1, Complutense University of Madrid2, Jet Propulsion Laboratory3, California Institute of Technology4, National Institute of Astrophysics, Optics and Electronics5, University of Florida6, Chalmers University of Technology7, Aix-Marseille University8, Durham University9, Steward Health Care System10, University of Toulouse11, University of Geneva12, University of Edinburgh13, Science and Technology Facilities Council14, Max Planck Society15, Institut d'Astrophysique de Paris16, University of Padua17, University of Birmingham18, Leiden University19, University of Colorado Boulder20, University of Tokyo21, Illinois Wesleyan University22, University of Pennsylvania23, University of Massachusetts Amherst24
TL;DR: In this article, the spectral energy distributions of 19 MIPS 24 μm-selected galaxies which are located behind the Bullet cluster (1E0657-56) were obtained from the Herschel Lensing Survey (HLS).
Abstract: The Herschel Lensing Survey (HLS) takes advantage of gravitational lensing by massive galaxy clusters to sample a population of high-redshift galaxies which are too faint to be detected above the confusion limit of current far-infrared/submillimeter telescopes. Measurements from 100–500 μm bracket the peaks of the far-infrared spectral energy distributions of these galaxies, characterizing their infrared luminosities and star formation rates. We introduce initial results from our science demonstration phase observations, directed toward the Bullet cluster (1E0657-56). By combining our observations with LABOCA 870 μm and AzTEC 1.1 mm data we fully constrain the spectral energy distributions of 19 MIPS 24 μm-selected galaxies which are located behind the cluster. We find that their colors are best fit using templates based on local galaxies with systematically lower infrared luminosities. This suggests that our sources are not like local ultra-luminous infrared galaxies in which vigorous star formation is contained in a compact highly dust-obscured region. Instead, they appear to be scaled up versions of lower luminosity local galaxies with star formation occurring on larger physical scales.
49 citations
California Institute of Technology1, Jet Propulsion Laboratory2, University of Arizona3, University of Toulouse4, Aix-Marseille University5, University of Geneva6, University of Edinburgh7, Science and Technology Facilities Council8, Max Planck Society9, Complutense University of Madrid10, Durham University11, Steward Health Care System12, University of Padua13, University of Birmingham14, Leiden University15
TL;DR: In this article, the authors have mapped 1E0657-56 (the Bullet cluster) with SPIRE with bands centered at 250, 350 and 500 μm and have detected the Sunyaev-Zel'dovich (SZ) effect at two longest wavelengths.
Abstract: The Sunyaev-Zel'dovich (SZ) effect is a spectral distortion of the cosmic microwave background as observed through the hot plasma in galaxy clusters This distortion is a decrement in the CMB intensity for λ > 13 mm, an increment at shorter wavelengths, and small again by λ ~ 250 μm As part of the Herschel Lensing Survey (HLS) we have mapped 1E0657–56 (the Bullet cluster) with SPIRE with bands centered at 250, 350 and 500 μm and have detected the SZ effect at the two longest wavelengths The measured SZ effect increment central intensities are ΔI_0 = 0097 ± 0019 MJy sr^(-1) at 350 μm and ΔI_0 = 0268 ± 0031 MJy sr^(-1) at 500 μm, consistent with the SZ effect spectrum derived from previous measurements at 2 mm No other diffuse emission is detected The presence of the finite temperature SZ effect correction is preferred by the SPIRE data at a significance of 21σ, opening the possibility that the relativistic SZ effect correction can be constrained by SPIRE in a sample of clusters The results presented here have important ramifications for both sub-mm measurements of galaxy clusters and blank field surveys with SPIRE
41 citations
University of Arizona1, University of Florida2, California Institute of Technology3, Complutense University of Madrid4, Durham University5, Jet Propulsion Laboratory6, University of Toulouse7, Aix-Marseille University8, University of Geneva9, Science and Technology Facilities Council10, University of Edinburgh11, Max Planck Society12, Steward Health Care System13, University of Padua14, University of Birmingham15, Leiden University16
TL;DR: In this article, the authors used deep, five band (100-500 μm) data from the Herschel Lensing Survey (HLS) to fully constrain the obscured star formation rate, SFR_(FIR), of galaxies in the Bullet cluster (z = 0.296), and a smaller background system (z= 0.35) in the same field.
Abstract: We use deep, five band (100–500 μm) data from the Herschel Lensing Survey (HLS) to fully constrain the obscured star formation rate, SFR_(FIR), of galaxies in the Bullet cluster (z = 0.296), and a smaller background system (z = 0.35) in the same field. Herschel detects 23 Bullet cluster members with a total SFRFIR = 144±14 M_☉ yr^(-1). On average, the background system contains brighter far-infrared (FIR) galaxies, with ~50% higher SFRFIR (21 galaxies; 207 ± 9 M_☉ yr^(-1)). SFRs extrapolated from 24 μm flux via recent templates (SFR_(24 µm)) agree well with SFRFIR for ~60% of the cluster galaxies. In the remaining ~40%, SFR24 µm underestimates SFR_(FIR) due to a significant excess in observed S_(100)/S_(24) (rest frame S_(75)/S_(18)) compared to templates of the same FIR luminosity.
37 citations
University of Arizona1, Complutense University of Madrid2, Aix-Marseille University3, Durham University4, Chalmers University of Technology5, California Institute of Technology6, Jet Propulsion Laboratory7, University of Toulouse8, University of Florida9, Ohio University10, University of Geneva11, University of Edinburgh12, Science and Technology Facilities Council13, Max Planck Society14, Steward Health Care System15, University of Padua16, University of Birmingham17, Leiden University18
TL;DR: In this article, a photometric procedure designed to recover robust fluxes and deblend faint Herschel sources near the confusion noise is described, based on the use of the positions of Spitzer/MIPS 24 μm sources as priors.
Abstract: We present preliminary results about the detection of high redshift (U)LIRGs in the Bullet cluster field by the PACS and SPIRE instruments within the Herschel Lensing Survey (HLS) Program. We describe in detail a photometric procedure designed to recover robust fluxes and deblend faint Herschel sources near the confusion noise. The method is based on the use of the positions of Spitzer/MIPS 24 μm sources as priors. Our catalogs are able to reliably (5σ) recover galaxies with fluxes above 6 and 10 mJy in the PACS 100 and 160 μm channels, respectively, and 12 to 18 mJy in the SPIRE bands. We also obtain spectral energy distributions covering the optical through the far-infrared/millimeter spectral ranges of all the Herschel detected sources, and analyze them to obtain independent estimations of the photometric redshift based on either stellar population or dust emission models. We exemplify the potential of the combined use of Spitzer position priors plus independent optical and IR photometric redshifts to robustly assign optical/NIR counterparts to the sources detected by Herschel and other (sub-)mm instruments.
36 citations
California Institute of Technology1, University of Chicago2, University of Illinois at Urbana–Champaign3, Northwestern University4, Goddard Space Flight Center5, Ames Research Center6, University of Western Ontario7, University of Minnesota8, University of Wisconsin-Madison9, Universities Space Research Association10
TL;DR: In this article, a far-infrared polarimeter for the HAWC instrument on SOFIA has been presented, which uses quartz half-wave plates continuously rotating at 0.5 Hz and fixed wire-grid polarizers.
Abstract: We describe our ongoing project to build a far-infrared polarimeter for the HAWC instrument on SOFIA. Far-IR
polarimetry reveals unique information about magnetic fields in dusty molecular clouds and is an important
tool for understanding star formation and cloud evolution. SOFIA provides flexible access to the infrared as
well as good sensitivity to and angular resolution of continuum emission from molecular clouds. We are making
progress toward outfitting HAWC, a first-generation SOFIA camera, with a four-band polarimeter covering 50 to
220 microns wavelength. We have chosen a conservative design which uses quartz half-wave plates continuously
rotating at ~0.5 Hz, ball bearing suspensions, fixed wire-grid polarizers, and cryogenic motors. Design challenges
are to fit the polarimeter into a volume that did not originally envision one, to minimize the heating of the
cryogenic optics, and to produce negligible interference in the detector system. Here we describe the performance
of the polarimeter measured at cryogenic temperature as well as the basic method we intend for data analysis.
We are on track for delivering this instrument early in the operating lifetime of SOFIA.
34 citations
TL;DR: In this article, the authors present an overview of the calibration and properties of data from the IRAC instrument aboard the Spitzer Space Telescope taken after the depletion of cryogen, and shortly afterward a two-month long calibration and characterization campaign was conducted.
Abstract: We present an overview of the calibration and properties of data from the IRAC instrument aboard the Spitzer Space Telescope taken after the depletion of cryogen. The cryogen depleted on 15 May 2009, and shortly afterward a two-month- long calibration and characterization campaign was conducted. The array temperature and bias setpoints were revised on 19 September 2009 to take advantage of lower than expected power dissipation by the instrument and to improve sensitivity. The final operating temperature of the arrays is 28.7 K, the applied bias across each detector is 500 mV and the equilibrium temperature of the instrument chamber is 27.55 K. The final sensitivities are essentially the same as the cryogenic mission with the 3.6 μm array being slightly less sensitive (10%) and the 4.5 μm array within 5% of the cryogenic sensitivity. The current absolute photometric uncertainties are 4% at 3.6 and 4.5 μm, and better than milli-mag photometry is achievable for long-stare photometric observations. With continued analysis, we expect the absolute calibration to improve to the cryogenic value of 3%. Warm IRAC operations fully support all science that was conducted in the cryogenic mission and all currently planned warm science projects (including Exploration Science programs). We expect that IRAC will continue to make ground-breaking discoveries in star formation, the nature of the early universe, and in our understanding of the properties of exoplanets.
15 citations
Jet Propulsion Laboratory1, National Institute of Standards and Technology2, Cornell University3, California Institute of Technology4, University of Toledo5, University of Arizona6, University of Texas at Austin7, University of Colorado Boulder8, University of California, Los Angeles9, University of Wyoming10
TL;DR: The Background-Limited Infrared-Submillimeter Spectrograph (BLISS) for SPICA was developed by as mentioned in this paper to provide a breakthrough capability for far-IR survey spectroscopy.
Abstract: We are developing the Background-Limited Infrared-Submillimeter Spectrograph (BLISS) for SPICA to provide a breakthrough capability for far-IR survey spectroscopy. SPICAs large cold aperture allows mid-IR to submm observations which are limited only by the natural backgrounds, and BLISS is designed to operate near this fundamental limit. BLISS-SPICA is 6 orders of magnitude faster than the spectrometers on Herschel and SOFIA in obtaining full-band spectra. It enables spectroscopy of dust-obscured galaxies at all epochs back to the rst billion years after the Big Bang (redshift 6), and study of all stages of planet formation in circumstellar disks. BLISS covers 35 - 433 microns range in ve or six wavelength bands, and couples two 2 sky positions simultaneously. The instrument is cooled to 50 mK for optimal sensitivity with an on-board refrigerators. The detector package is 4224 silicon-nitride micro-mesh leg-isolated bolometers with superconducting transition-edge-sensed (TES) thermistors, read out with a cryogenic time-domain multiplexer. All technical elements of BLISS have heritage in mature scientic instruments, and many have own. We report on our design study in which we are optimizing performance while accommodating SPICAs constraints, including the stringent cryogenic mass budget. In particular, we present our progress in the optical design and waveguide spectrometer prototyping. A companion paper in Conference 7741 (Beyer et al.) discusses in greater detail the progress in the BLISS TES bolometer development.
5 citations
TL;DR: A key to the success of the Spitzer Space Telescope (formerly SIRTF) mission was a unique management structure that promoted open communication and collaboration among scientific, engineering, and contractor personnel at all levels of the project as discussed by the authors.
Abstract: A key to the success of the Spitzer Space Telescope (formerly SIRTF) Mission was a unique management structure that
promoted open communication and collaboration among scientific, engineering, and contractor personnel at all levels of
the project. This helped us to recruit and maintain the very best people to work on Spitzer. We describe the management
concept that led to the success of the mission. Specific examples of how the project benefited from the communication
and reporting structure, and lessons learned about technology are described.
University of Arizona1, Complutense University of Madrid2, California Institute of Technology3, Jet Propulsion Laboratory4, National Institute of Astrophysics, Optics and Electronics5, University of Florida6, Chalmers University of Technology7, Aix-Marseille University8, Durham University9, Steward Health Care System10, University of Toulouse11, University of Geneva12, University of Edinburgh13, Science and Technology Facilities Council14, Max Planck Society15, Institut d'Astrophysique de Paris16, University of Padua17, University of Birmingham18, Leiden University19, University of Colorado Boulder20, University of Tokyo21, Illinois Wesleyan University22, University of Pennsylvania23, University of Massachusetts Amherst24
TL;DR: In this article, the spectral energy distributions of 19 MIPS 24 micron selected galaxies which are located behind the Bullet cluster were analyzed using templates based on local ultra-luminous infrared galaxies with systematically lower infrared luminosities.
Abstract: The Herschel Lensing Survey (HLS) takes advantage of gravitational lensing by massive galaxy clusters to sample a population of high-redshift galaxies which are too faint to be detected above the confusion limit of current far-infrared/submillimeter telescopes. Measurements from 100-500 micron bracket the peaks of the far-infrared spectral energy distributions of these galaxies, characterizing their infrared luminosities and star formation rates. We introduce initial results from our science demonstration phase observations, directed toward the Bullet cluster (1E0657-56). By combining our observations with LABOCA 870 micron and AzTEC 1.1 mm data we fully constrain the spectral energy distributions of 19 MIPS 24 micron selected galaxies which are located behind the cluster. We find that their colors are best fit using templates based on local galaxies with systematically lower infrared luminosities.This suggests that our sources are not like local ultra-luminous infrared galaxies in which vigorous star formation is contained in a compact highly dust-obscured region. Instead, they appear to be scaled up versions of lower luminosity local galaxies with star formation occurring on larger physical scales.
University of Arizona1, University of Florida2, California Institute of Technology3, Complutense University of Madrid4, Durham University5, Jet Propulsion Laboratory6, Aix-Marseille University7, University of Toulouse8, University of Geneva9, University of Edinburgh10, Science and Technology Facilities Council11, Max Planck Society12, Steward Health Care System13, University of Padua14, University of Birmingham15, Leiden University16
TL;DR: In this paper, the authors used deep, five band (100-500um) data from the Herschel Lensing Survey (HLS) to fully constrain the obscured star formation rate, SFR_FIR, of galaxies in the Bullet cluster (z=0.296), and a smaller background system (z =0.35) in the same field.
Abstract: We use deep, five band (100-500um) data from the Herschel Lensing Survey (HLS) to fully constrain the obscured star formation rate, SFR_FIR, of galaxies in the Bullet cluster (z=0.296), and a smaller background system (z=0.35) in the same field. Herschel detects 23 Bullet cluster members with a total SFR_FIR = 144 +/- 14 M_sun yr^-1. On average, the background system contains brighter far-infrared (FIR) galaxies, with ~50% higher SFR_FIR (21 galaxies; 207 +/- 9 M_sun yr^-1). SFRs extrapolated from 24um flux via recent templates (SFR_24) agree well with SFR_FIR for ~60% of the cluster galaxies. In the remaining ~40%, SFR_24 underestimates SFR_FIR due to a significant excess in observed S_100/S_24 (rest frame S_75/S_18) compared to templates of the same FIR luminosity.