G. J. Stacey

Cornell University, Итак, New York, United States

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Publications (307)571.29 Total impact

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    ABSTRACT: With ~ 4 x 10 7 M � of warm molecular gas and dust responding to the deep potential well of the nuclear stellar bulge and the Galactic black hole, the 300-pc diameter central molecular zone (CMZ) of our Galaxy represents the Galaxy’s most massive concentration of dense gas, and is an essential template for understanding the phenomenology of gas-rich galactic nuclei in general. Because it is a few hundred times closer than even the nearest active galactic nucleus or starburst nucleus, the Galactic center (GC) offers us critical information about how the activity of a galactic nucleus is produced by the interactions of the multitude of contributors: the central black hole, massive stars, dense clouds, strong magnetic fields, an intense X-ray background, and other forms of high-energy radiation. Because of the 20 – 30 magnitudes of visual extinction to the GC, its abundant energy is well represented in the IR and submillimeter, where, with anticipated angular and spectral resolution, we have the best opportunity to unscramble the details of this complex region. Figure 1: Infrared view of the inner 500 pc of the Galaxy, from the legacy programs of the Spitzer Space Telescope. Blue & green: measurements at 3.6 & 8.0 µm with the IRAC camera; red: 24 µm image from the MIPS camera. The CMZ occupies the central 300 pc of the Galactic plane. Here, we focus on three important, unsolved questions about the Galactic center
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    ABSTRACT: We have detected the 158 {\mu}m [CII] line from 12 galaxies at z~1-2. This is the first survey of this important starformation tracer at redshifts covering the epoch of maximum star-formation in the Universe and quadruples the number of reported high z [CII] detections. The line is very luminous, between <0.024-0.65% of the far-infrared continuum luminosity of our sources, and arises from PDRs on molecular cloud surfaces. An exception is PKS 0215+015, where half of the [CII] emission could arise from XDRs near the central AGN. The L[CII] /LFIR ratio in our star-formation-dominated systems is ~8 times larger than that of our AGN-dominated systems. Therefore this ratio selects for star-formation-dominated systems. Furthermore, the L[CII]/LFIR and L[CII]/L(CO(1-0)) ratios in our starforming galaxies and nearby starburst galaxies are the same, so that luminous starforming galaxies at earlier epochs (z~1-2) appear to be scaled up versions of local starbursts entailing kilo-parsec-scale starbursts. Most of the FIR and [CII] radiation from our AGN-dominated sample (excepting PKS 0215+015) also arises from kpc scale starformation, but with far-UV radiation fields ~8 times more intense than in our star-formation-dominated sample. We speculate that the onset of AGN activity stimulates large-scale star-formation activity within AGN-dominated systems. This idea is supported by the relatively strong [OIII] line emission, indicating very young stars, that was recently observed in high z composite AGN/starburst systems. Our results confirm the utility of the [CII] line, and in particular, the L[CII]/L(FIR) and L[CII]/LCO(1-0) ratios as a tracers of star-formation in galaxies at high redshifts.
    The Astrophysical Journal 12/2010; 724(2):957-974. DOI:10.1088/0004-637X/724/2/957 · 6.28 Impact Factor
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    ABSTRACT: ZEUS-2, the second generation (z)Redshift and Early Universe Spectrometer, like its predecessor is a moderate resolution (R~1000) long-slit, echelle grating spectrometer optimized for the detection of faint, broad lines from distant galaxies. It is designed for studying star-formation across cosmic time. ZEUS-2 employs three TES bolometer arrays (555 pixels total) to deliver simultaneous, multi-beam spectra in up to 4 submillimeter windows. The NIST Boulder-built arrays operate at ~100mK and are readout via SQUID multiplexers and the Multi-Channel Electronics from the University of British Columbia. The instrument is cooled via a pulse-tube cooler and two-stage ADR. Various filter configurations give ZEUS-2 access to 7 different telluric windows from 200 to 850 micron enabling the simultaneous mapping of lines from extended sources or the simultaneous detection of the 158 micron [CII] line and the [NII] 122 or 205 micron lines from z = 1-2 galaxies. ZEUS-2 is designed for use on the CSO, APEX and possibly JCMT.
    Proceedings of SPIE - The International Society for Optical Engineering 10/2010; DOI:10.1117/12.857018 · 0.20 Impact Factor
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    ABSTRACT: We have studied the molecular hydrogen energetics of the edge-on spiral galaxy NGC 891, using a 34 position map in the lowest three pure rotational H2 lines observed with the Spitzer Infrared Spectrograph. The S(0), S(1), and S(2) lines are bright with an extinction-corrected total luminosity of ~2.8 × 107 L sun, or 0.09% of the total-infrared luminosity of NGC 891. The H2 line ratios are nearly constant along the plane of the galaxy---we do not observe the previously reported strong drop-off in the S(1)/S(0) line intensity ratio in the outer regions of the galaxy, so we find no evidence for the very massive cold CO-free molecular clouds invoked to explain the past observations. The H2 level excitation temperatures increase monotonically indicating that there is more than one component to the emitting gas. More than 99% of the mass is in the lowest excitation (T ex ~ 125 K) "warm" component. In the inner galaxy, the warm H2 emitting gas is ~16% of the CO(1-0)-traced cool molecular gas, while in the outer regions the fraction is twice as high. This large mass of warm gas is heated by a combination of the far-UV photons from stars in photodissociation regions (PDRs) and the dissipation of turbulent kinetic energy. Including the observed far-infrared [O I] and [C II] fine-structure line emission and far-infrared continuum emission in a self-consistent manner to constrain the PDR models, we find essentially all of the S(0) and most (70%) of the S(1) line arise from low excitation PDRs, while most (80%) of the S(2) and the remainder of the S(1) line emission arise from low-velocity microturbulent dissipation.
    The Astrophysical Journal 09/2010; 721(1):59-73. DOI:10.1088/0004-637X/721/1/59 · 6.28 Impact Factor
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    ABSTRACT: We have studied the molecular hydrogen energetics of the edge-on spiral galaxy NGC\,891, using a 34-position map in the lowest three pure rotational H$_2$ lines observed with the Spitzer Infrared Spectrograph. The S(0), S(1), and S(2) lines are bright with an extinction corrected total luminosity of $\sim2.8 \times 10^{7}$ L$_{\odot}$, or 0.09\% of the total-infrared luminosity of NGC\,891. The H$_2$ line ratios are nearly constant along the plane of the galaxy -- we do not observe the previously reported strong drop-off in the S(1)/S(0) line intensity ratio in the outer regions of the galaxy, so we find no evidence for the very massive cold CO-free molecular clouds invoked to explain the past observations. The H$_2$ level excitation temperatures increase monotonically indicating more than one component to the emitting gas. More than 99\% of the mass is in the lowest excitation (T$_{ex}$ $\sim$125 K) ``warm'' component. In the inner galaxy, the warm H$_2$ emitting gas is $\sim$15\% of the CO(1-0)-traced cool molecular gas, while in the outer regions the fraction is twice as high. This large mass of warm gas is heated by a combination of the far-UV photons from stars in photo-dissociation regions (PDRs) and the dissipation of turbulent kinetic energy. Including the observed far-infrared [OI] and [CII] fine-structure line emission and far-infrared continuum emission in a self-consistent manner to constrain the PDR models, we find essentially all of the S(0) and most (70\%) of the S(1) line arises from low excitation PDRs, while most (80\%) of the S(2) and the remainder of the S(1) line emission arises from low velocity microturbulent dissipation. Comment: Accepted for publication in The Astrophysical Journal. Figure 10 available at http://www.physics.uoc.gr/~vassilis/papers/ngc891.pdf
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    Article: CCAT optics
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    ABSTRACT: CCAT will be a 25 m diameter, submillimeter-wave telescope. It will be located on Cerro Chajnantor in the Atacama Desert, near ALMA. CCAT will be an on-axis, Ritchey-Chrétien design with an active primary to compensate gravitational deformations. The primary mirror will have 162 segments, each with ~0.5 × 0.5 m reflecting tiles on a ~2×2 m, insulated, carbon-fiber-reinforced-plastic subframe. CCAT will be equipped with wide-field, multi-color cameras and multi-object spectrometers at its Nasmyth foci. These instruments will cover all the atmospheric windows in the λ = 0.2 to 2 mm range. The field of view at the Nasmyth foci will be 1°, so CCAT will be able to support cameras with a few ×10^4 detectors (spaced 2 beamwidths) at λ = 1 mm to a few ×10^6 detectors (spaced half a beamwidth) at λ = 350 μm. Single instruments of this size are probably impractical, so we will break the field into smaller pieces, with a separate sub-field camera for each piece. The cameras will require some relay optics to couple the fairly slow beam from the telescope to the detectors. A reflective relay for 1° field of view is too large to be practical, so we plan to use a compact, cold, refractive relay in each sub-field camera.
    Proceedings of SPIE - The International Society for Optical Engineering 07/2010; DOI:10.1117/12.856489 · 0.20 Impact Factor
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    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.
    Proceedings of SPIE - The International Society for Optical Engineering 07/2010; DOI:10.1117/12.857779 · 0.20 Impact Factor
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    ABSTRACT: FORCAST is the "first light" U. S. science instrument to fly aboard SOFIA. FORCAST offers dual channel imaging in discrete filters at 5 - 25 microns and 30 - 40 microns, with diffraction-limited imaging at wavelengths > 15 microns. FORCAST has a plate scale of 0.75 arcsec per pixel, giving it a 3.2 arcmin x 3.2 arcmin FOV on SOFIA. We give a status update on FORCAST development, including the performance of new far-IR filters; design and performance of the calibration box; laboratory operations and performance; and results from ground-based and first flight operations.
    Proceedings of SPIE - The International Society for Optical Engineering 07/2010; DOI:10.1117/12.857049 · 0.20 Impact Factor
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    ABSTRACT: Context. Over the past few years several studies have provided estimates of the SFR (star-formation rate) or the total infrared luminosity from just one infrared band. However these relations are generally derived for entire galaxies, which are known to contain a large scale diffuse emission that is not necessarily related to the latest star-formation episode. Aims. We provide new relations to estimate the SFR from resolved star-forming regions at 100 μm and 160 μm. Methods. We select individual star-forming regions in the nearby (840 kpc) galaxy M33. We estimate the SFR combining the emission in Hα and at 24 μm to calibrate the emission at 100 μm and 160 μm as SFR estimators, as mapped with PACS/Herschel. The data are obtained in the framework of the HERM33ES open time key program. Results. There is less emission in the HII regions at 160 μm than at 100 μm. Over a dynamic range of almost 2 dex in Σ_(SFR) we find that the 100 μm emission is a nearly linear estimator of the SFR, whereas that at 160 μm is slightly superlinear. Conclusions. The behaviour of individual star-forming regions is surprisingly similar to that of entire galaxies. At high Σ_(SFR), star formation drives the dust temperature, whereas uncertainties and variations in radiation-transfer and dust-heated processes dominate at low Σ_(SFR). Detailed modelling of both galaxies and individual star forming regions will be needed to interpret similarities and differences between the two and assess the fraction of diffuse emission in galaxies.
    Astronomy and Astrophysics 07/2010; 518. DOI:10.1051/0004-6361/201014649 · 4.48 Impact Factor
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    ABSTRACT: The Ultra Luminous InfraRed Galaxy Mrk 231 reveals up to seven rotational lines of water (H2O) in emission, including a very high-lying (E_{upper}=640 K) line detected at a 4sigma level, within the Herschel/SPIRE wavelength range, whereas PACS observations show one H2O line at 78 microns in absorption, as found for other H2O lines previously detected by ISO. The absorption/emission dichotomy is caused by the pumping of the rotational levels by far-infrared radiation emitted by dust, and subsequent relaxation through lines at longer wavelengths, which allows us to estimate both the column density of H2O and the general characteristics of the underlying far-infrared continuum source. Radiative transfer models including excitation through both absorption of far-infrared radiation emitted by dust and collisions are used to calculate the equilibrium level populations of H2O and the corresponding line fluxes. The highest-lying H2O lines detected in emission, with levels at 300-640 K above the ground state, indicate that the source of far-infrared radiation responsible for the pumping is compact (radius=110-180 pc) and warm (T_{dust}=85-95 K), accounting for at least 45% of the bolometric luminosity. The high column density, N(H2O)~5x10^{17} cm^{-2}, found in this nuclear component, is most probably the consequence of shocks/cosmic rays, an XDR chemistry, and/or an "undepleted chemistry" where grain mantles are evaporated. A more extended region, presumably the inner region of the 1-kpc disk observed in other molecular species, could contribute to the flux observed in low-lying H2O lines through dense hot cores, and/or shocks. The H2O 78 micron line observed with PACS shows hints of a blue-shifted wing seen in absorption, possibly indicating the occurrence of H2O in the prominent outflow detected in OH (Fischer et al., this volume).
    Astronomy and Astrophysics 05/2010; 518. DOI:10.1051/0004-6361/201014664 · 4.48 Impact Factor
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    ABSTRACT: We present a full high resolution SPIRE FTS spectrum of the nearby ultraluminous infrared galaxy Mrk 231. In total 25 lines are detected, including CO J = 5-4 through J = 13-12, 7 rotational lines of H2O, 3 of OH+ and one line each of H2O+, CH+, and HF. We find that the excitation of the CO rotational levels up to J = 8 can be accounted for by UV radiation from star formation. However, the approximately flat luminosity distribution of the CO lines over the rotational ladder above J = 8 requires the presence of a separate source of excitation for the highest CO lines. We explore X-ray heating by the accreting supermassive black hole in Mrk 231 as a source of excitation for these lines, and find that it can reproduce the observed luminosities. We also consider a model with dense gas in a strong UV radiation field to produce the highest CO lines, but find that this model strongly overpredicts the hot dust mass in Mrk 231. Our favoured model consists of a star forming disk of radius 560 pc, containing clumps of dense gas exposed to strong UV radiation, dominating the emission of CO lines up to J = 8. X-rays from the accreting supermassive black hole in Mrk 231 dominate the excitation and chemistry of the inner disk out to a radius of 160 pc, consistent with the X-ray power of the AGN in Mrk 231. The extraordinary luminosity of the OH+ and H2O+ lines reveals the signature of X-ray driven excitation and chemistry in this region.
    Astronomy and Astrophysics 05/2010; 518. DOI:10.1051/0004-6361/201014682 · 4.48 Impact Factor
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    ABSTRACT: Within the framework of the HERM33ES key project, we are studying the star forming interstellar medium in the nearby, metal-poor spiral galaxy M33, exploiting the high resolution and sensitivity of Herschel. We use PACS and SPIRE maps at 100, 160, 250, 350, and 500 micron wavelength, to study the variation of the spectral energy distributions (SEDs) with galacto-centric distance. Detailed SED modeling is performed using azimuthally averaged fluxes in elliptical rings of 2 kpc width, out to 8 kpc galacto-centric distance. Simple isothermal and two-component grey body models, with fixed dust emissivity index, are fitted to the SEDs between 24 and 500 micron using also MIPS/Spitzer data, to derive first estimates of the dust physical conditions. The far-infrared and submillimeter maps reveal the branched, knotted spiral structure of M33. An underlying diffuse disk is seen in all SPIRE maps (250-500 micron). Two component fits to the SEDs agree better than isothermal models with the observed, total and radially averaged flux densities. The two component model, with beta fixed at 1.5, best fits the global and the radial SEDs. The cold dust component clearly dominates; the relative mass of the warm component is less than 0.3% for all the fits. The temperature of the warm component is not well constrained and is found to be about 60K plus/minus 10K. The temperature of the cold component drops significantly from about 24K in the inner 2 kpc radius to 13K beyond 6 kpc radial distance, for the best fitting model. The gas-to-dust ratio for beta=1.5, averaged over the galaxy, is higher than the solar value by a factor of 1.5 and is roughly in agreement with the subsolar metallicity of M33.
    Astronomy and Astrophysics 05/2010; 518. DOI:10.1051/0004-6361/201014613 · 4.48 Impact Factor
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    ABSTRACT: Within the framework of the HERM33ES Key Project, using the high resolution and sensitivity of the Herschel photometric data, we study the compact emission in the Local Group spiral galaxy M33 to investigate the nature of the compact SPIRE emission sources. We extracted a catalogue of sources at 250um in order to investigate the nature of this compact emission. Taking advantage of the unprecedented Herschel resolution at these wavelengths, we also focus on a more precise study of some striking Halpha shells in the northern part of the galaxy. We present a catalogue of 159 compact emission sources in M33 identified by SExtractor in the 250um SPIRE band that is the one that provides the best spatial resolution. We also measured fluxes at 24um and Halpha for those 159 extracted sources. The morphological study of the shells also benefits from a multiwavelength approach including Halpha, far-UV from GALEX, and infrared from both Spitzer IRAC 8um and MIPS 24um in order to make comparisons. For the 159 compact sources selected at 250um, we find a very strong Pearson correlation coefficient with the MIPS 24um emission (r24 = 0.94) and a rather strong correlation with the Halpha emission, although with more scatter (rHa = 0.83). The morphological study of the Halpha shells shows a displacement between far-ultraviolet, Halpha, and the SPIRE bands. The cool dust emission from SPIRE clearly delineates the Halpha shell structures. The very strong link between the 250um compact emission and the 24um and Halpha emissions, by recovering the star formation rate from standard recipes for HII regions, allows us to provide star formation rate calibrations based on the 250um compact emission alone. The different locations of the Halpha and far-ultraviolet emissions with respect to the SPIRE cool dust emission leads to a dynamical age of a few Myr for the Halpha shells and the associated cool dust. Comment: 4 pages, 3 figures, Accpeted for publication in the A&A Herschel Special Issue
    Astronomy and Astrophysics 05/2010; 518. DOI:10.1051/0004-6361/201014607 · 4.48 Impact Factor
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    ABSTRACT: Over the past few years several studies have provided estimates of the SFR (star-formation rate) or the total infrared luminosity from just one infrared band. However these relations are generally derived for entire galaxies, which are known to contain a large scale diffuse emission that is not necessarily related to the latest star-formation episode. We provide new relations to estimate the SFR from resolved star-forming regions at 100 mum and 160 mum. We select individual star-forming regions in the nearby (840 kpc) galaxy M33. We estimate the SFR combining the emission in Halpha and at 24 mum to calibrate the emission at 100 mum and 160 mum as SFR estimators, as mapped with PACS/Herschel. The data are obtained in the framework of the HERM33ES open time key project. There is less emission in the HII regions at 160 mum than at 100 mum. Over a dynamic range of almost 2 dex in Sigma(SFR) we find that the 100 mum emission is a nearly linear estimator of the SFR, whereas that at 160 mum is slightly superlinear. The behaviour of individual star-forming regions is surprisingly similar to that of entire galaxies. At high Sigma(SFR), star formation drives the dust temperature, whereas uncertainties and variations in radiation-transfer and dust-heated processes dominate at low Sigma(SFR). Detailed modelling of both galaxies and individual star forming regions will be needed to interpret similarities and differences between the two and assess the fraction of diffuse emission in galaxies. Comment: 5 pages, 3 figures, accepted for publication in the A&A Herschel special issue
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    ABSTRACT: We have made the first detections of the 88 mum [O III] line from galaxies in the early universe, detecting the line from the lensed active galactic nucleus (AGN)/starburst composite systems APM 08279+5255 at z = 3.911 and SMM J02399-0136 at z = 2.8076. The line is exceptionally bright from both systems, with apparent (lensed) luminosities ~1011 L sun. For APM 08279, the [O III] line flux can be modeled in a star formation paradigm, with the stellar radiation field dominated by stars with effective temperatures, T eff > 36,000 K, similar to the starburst found in M82. The model implies ~35% of the total far-IR luminosity of the system is generated by the starburst, with the remainder arising from dust heated by the AGN. The 88 mum line can also be generated in the narrow-line region of the AGN if gas densities are around a few 1000 cm-3. For SMM J02399, the [O III] line likely arises from H II regions formed by hot (T eff > 40,000 K) young stars in a massive starburst that dominates the far-IR luminosity of the system. The present work demonstrates the utility of the [O III] line for characterizing starbursts and AGN within galaxies in the early universe. These are the first detections of this astrophysically important line from galaxies beyond a redshift of 0.05.
    The Astrophysical Journal 05/2010; 714(1). DOI:10.1088/2041-8205/714/1/L147 · 6.28 Impact Factor
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    ABSTRACT: We report the detection of 158 mum [C II] fine-structure line emission from MIPS J142824.0+352619, a hyperluminous (L IR ~ 1013 L sun) starburst galaxy at z = 1.3. The line is bright, corresponding to a fraction L [C II]/L FIR &ap; 2 × 10-3 of the far-IR (FIR) continuum. The [C II], CO, and FIR continuum emission may be modeled as arising from photodissociation regions (PDRs) that have a characteristic gas density of n ~ 104.2 cm-3, and that are illuminated by a far-UV radiation field ~103.2 times more intense than the local interstellar radiation field. The mass in these PDRs accounts for approximately half of the molecular gas mass in this galaxy. The L [C II]/L FIR ratio is higher than observed in local ultraluminous infrared galaxies or in the few high-redshift QSOs detected in [C II], but the L [C II]/L FIR and L CO/L FIR ratios are similar to the values seen in nearby starburst galaxies. This suggests that MIPS J142824.0+352619 is a scaled-up version of a starburst nucleus, with the burst extended over several kiloparsecs. Bibtex entry for this abstract Preferred format for this abstract (see Preferences) Find Similar Abstracts: Use: Authors Title Keywords (in text query field) Abstract Text Return: Query Results Return items starting with number Query Form Database: Astronomy Physics arXiv e-prints
    The Astrophysical Journal Letters 05/2010; 714(1). DOI:10.1088/2041-8205/714/1/L162 · 5.60 Impact Factor
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    ABSTRACT: We report the detection of 158 micron [CII] fine-structure line emission from MIPS J142824.0+352619, a hyperluminous (L_IR ~ 10^13 L_sun) starburst galaxy at z=1.3. The line is bright, and corresponds to a fraction L_[CII]/L_FIR = 2 x 10^-3 of the far-IR (FIR) continuum. The [CII], CO, and FIR continuum emission may be modeled as arising from photodissociation regions (PDRs) that have a characteristic gas density of n ~ 10^4.2 cm^-3, and that are illuminated by a far-UV radiation field ~10^3.2 times more intense than the local interstellar radiation field. The mass in these PDRs accounts for approximately half of the molecular gas mass in this galaxy. The L_[CII]/L_FIR ratio is higher than observed in local ULIRGs or in the few high-redshift QSOs detected in [CII], but the L_[CII]/L_FIR and L_CO/L_FIR ratios are similar to the values seen in nearby starburst galaxies. This suggests that MIPS J142824.0+352619 is a scaled-up version of a starburst nucleus, with the burst extended over several kiloparsecs. Comment: 6 pages, 3 figures, accepted by ApJ Letters
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    ABSTRACT: We report the detection of the [CII]158 micron fine structure line from six submillimeter galaxies with redshifts between 1.12 and 1.73. This more than doubles the total number of [CII]158 micron detections reported from high redshift sources. These observations were made with the Redshift(z) and Early Universe Spectrometer(ZEUS) at the Caltech Submillimeter Observatory on Mauna Kea, Hawaii between December 2006 and March 2009. ZEUS is a background limited submm echelle grating spectrometer (Hailey-Dunsheath 2009). Currently we are constructing ZEUS-2. This new instrument will utilize the same grating but will feature a two dimensional transition-edge sensed bolometer array with SQUID multiplexing readout system enabling simultaneous background limited observations in the 200, 340, 450 and 650 micron telluric windows. ZEUS-2 will allow for long slit imaging spectroscopy in nearby galaxies and a [CII] survey from z 0.25 to 2.5.
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    ABSTRACT: An updated Science Vision for the SOFIA project is presented, including an overview of the characteristics and capabilities of the observatory and first generation instruments. A primary focus is placed on four science themes: 'The Formation of Stars and Planets', 'The Interstellar Medium of the Milky Way', 'Galaxies and the Galactic Center' and 'Planetary Science'. Comment: 128 pages pdf format Version 2 corrects: Attribution for Figure 5-1 Definition of "SIS" Affiliation of one of the contributors to the Science Vision
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    ABSTRACT: When and how did galaxies form and their metals accumulate? Over the last decade, this has moved from an archeological question to a live investigation: there is now a broad picture of the evolution of galaxies in dark matter halos: their masses, stars, metals and supermassive blackholes. Galaxies have been found and studied in which these formation processes are taking place most vigorously, all the way back in cosmic time to when the intergalactic medium (IGM) was still largely neutral. However, the details of how and why the interstellar medium (ISM) in distant galaxies cools, is processed, recycled and enriched in metals by stars, and fuels active galactic nuclei (AGNs) remain uncertain. In particular, the cooling of gas to fuel star formation, and the chemistry and physics of the most intensely active regions is hidden from view at optical wavelengths, but can be seen and diagnosed at mid- & far-infrared (IR) wavelengths. Rest-frame IR observations are important first to identify the most luminous, interesting and important galaxies, secondly to quantify accurately their total luminosity, and finally to use spectroscopy to trace the conditions in the molecular and atomic gas out of which stars form. In order to map out these processes over the full range of environments and large-scale structures found in the universe - from the densest clusters of galaxies to the emptiest voids - we require tools for deep, large area surveys, of millions of galaxies out to z~5, and for detailed follow-up spectroscopy. The necessary tools can be realized technically. Here, we outline the requirements for gathering the crucial information to build, validate and challenge models of galaxy evolution.

Publication Stats

3k Citations
571.29 Total Impact Points

Institutions

  • 1992–2015
    • Cornell University
      • Department of Astronomy
      Итак, New York, United States
  • 2014
    • University of Lethbridge
      Lethbridge, Alberta, Canada
  • 1988–2009
    • University of California, Berkeley
      • Department of Physics
      Berkeley, CA, United States
  • 2001–2005
    • California Institute of Technology
      • Infrared Processing and Analysis Center
      Pasadena, California, United States
  • 1993–1999
    • University of Texas at Austin
      • Department of Astronomy
      Austin, Texas, United States
  • 1997
    • Cornell College
      Cornell, Wisconsin, United States
  • 1996
    • University of Wyoming
      Laramie, Wyoming, United States
  • 1991–1993
    • Boston University
      Boston, Massachusetts, United States
  • 1982
    • Harvard University
      Cambridge, Massachusetts, United States