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Astronomy Department Faculty Publication Series

2010

Articles 31 - 60 of 89

Full-Text Articles in Physical Sciences and Mathematics

Intergalactic Dust Extinction In Hydrodynamic Cosmological Simulations, Y Zu, Dh Weinberg, R Dave, M Fardal, N Katz, D Keres, B Oppenheimer Jan 2010

Intergalactic Dust Extinction In Hydrodynamic Cosmological Simulations, Y Zu, Dh Weinberg, R Dave, M Fardal, N Katz, D Keres, B Oppenheimer

Astronomy Department Faculty Publication Series

Recently Ménard et al. (hereafter MSFR) detected a subtle but systematic change in the mean colour of quasars as a function of their projected separation from foreground galaxies, extending to comoving separations of ∼10 h−1 Mpc, which they interpret as a signature of reddening by intergalactic dust. We present theoretical models of this remarkable observation, using smoothed particle hydrodynamic cosmological simulations of a (50 h−1 Mpc)3 volume. Our primary model uses a simulation with galactic winds and assumes that dust traces the intergalactic metals. The predicted galaxy–dust correlation function is similar in form to the galaxy–mass correlation …

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Testing Subhalo Abundance Matching In Cosmological Smoothed Particle Hydrodynamics Simulations, V Simha, D Weinberg, R Dave, M Fardal, N Katz, B Oppenheimer Jan 2010

Testing Subhalo Abundance Matching In Cosmological Smoothed Particle Hydrodynamics Simulations, V Simha, D Weinberg, R Dave, M Fardal, N Katz, B Oppenheimer

Astronomy Department Faculty Publication Series

Subhalo abundance matching (SHAM) is a technique for populating simulated dark matter distributions with galaxies, assuming a monotonic relation between a galaxy's stellar mass or luminosity and the mass of its parent dark matter halo or subhalo. We examine the accuracy of SHAM in two cosmological SPH simulations, one of which includes momentum-driven winds. The SPH simulations indeed show a nearly monotonic relation between stellar mass and halo mass provided that, for satellite galaxies, we use the mass of the subhalo at the epoch when it became a satellite. In each simulation, the median relation for central and satellite galaxies …

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Feedback And Recycled Wind Accretion: Assembling The Z = 0 Galaxy Mass Function, Bd Oppenheimer, R Dave, D Keres, M Fardal, N Katz, Ja Kollmeier, D Weinberg Jan 2010

Feedback And Recycled Wind Accretion: Assembling The Z = 0 Galaxy Mass Function, Bd Oppenheimer, R Dave, D Keres, M Fardal, N Katz, Ja Kollmeier, D Weinberg

Astronomy Department Faculty Publication Series

We analyse cosmological hydrodynamic simulations that include observationally-constrained prescriptions for galactic outflows. If these simulated winds accurately represent winds in the real Universe, then material previously ejected in winds provides the dominant source of gas infall for new star formation at redshifts z<1. This recycled wind accretion, or wind mode, provides a third physically distinct accretion channel in addition to the "hot" and "cold" modes emphasised in recent theoretical studies. Because of the interaction between outflows and gas in and around halos, the recycling timescale of wind material (t_rec) is shorter in higher-mass systems, which reside in denser gaseous environments. In these simulations, this differential recycling plays a central role in shaping the present-day galaxy stellar mass function (GSMF). If we remove all particles that were ever ejected in a wind, then the predicted GSMFs are much steeper than observed; galaxy masses are suppressed both by the direct removal of gas and by the hydrodynamic heating of their surroundings, which reduces subsequent infall. With wind recycling included, the simulation that incorporates our favoured momentum-driven wind scalings reproduces the observed GSMF for stellar masses 10^9 < M < 5x10^10 Msolar. At higher masses, wind recycling leads to excessive galaxy masses and excessive star formation rates relative to observations. In these massive systems, some quenching mechanism must suppress the re-accretion of gas ejected from star-forming galaxies. In short, as has long been anticipated, the form of the GSMF is governed by outflows; the unexpected twist here for our simulated winds is that it is not primarily the ejection of material but how the ejected material is re-accreted that governs the GSMF.

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Discovery Of A Luminous Blue Variable With An Ejection Nebula Near The Quintuplet Cluster, Jc Mauerhan, Mr Morris, A Cotera, H Dong, Qd Wang, Sr Stolovy, C Lang, Is Glass Jan 2010

Discovery Of A Luminous Blue Variable With An Ejection Nebula Near The Quintuplet Cluster, Jc Mauerhan, Mr Morris, A Cotera, H Dong, Qd Wang, Sr Stolovy, C Lang, Is Glass

Astronomy Department Faculty Publication Series

We report on the discovery of a luminous blue variable (LBV) lying 7 pc in projection from the Quintuplet cluster. This source, which we call LBV G0.120 – 0.048, was selected for spectroscopy owing to its detection as a strong source of Paschen-α (Pα) excess in a recent narrowband imaging survey of the Galactic center region with the Hubble Space Telescope/Near-Infrared Camera and Multi-Object Spectrometer. The K-band spectrum is similar to that of the Pistol Star and other known LBVs. The new LBV was previously cataloged as a photometric variable star, exhibiting brightness fluctuations of up to 1 …

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Variable O Vi And N V Emission From The X-Ray Binary Lmc X-3: Heating Of The Black Hole Companion*, L Song, Tm Tripp, Qd Wang, Y Yao, W Cui, Y Xue, Ja Orosz, D Steeghs, Jf Steiner, Map Torres, Je Mcclintock Jan 2010

Variable O Vi And N V Emission From The X-Ray Binary Lmc X-3: Heating Of The Black Hole Companion*, L Song, Tm Tripp, Qd Wang, Y Yao, W Cui, Y Xue, Ja Orosz, D Steeghs, Jf Steiner, Map Torres, Je Mcclintock

Astronomy Department Faculty Publication Series

Based on high-resolution ultraviolet spectroscopy obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE) and the Cosmic Origins Spectrograph, we present new detections of O VI and N V emission from the black hole X-ray binary (XRB) system LMC X-3. We also update the ephemeris of the XRB using recent radial velocity measurements obtained with the echelle spectrograph on the Magellan-Clay telescope. We observe significant velocity variability of the UV emission, and we find that the O VI and N V emission velocities follow the optical velocity curve of the XRB. Moreover, the O VI and N V intensities regularly decrease …

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The Radio Properties And Magnetic Field Configuration In The Crab-Like Pulsar Wind Nebula G54.1+0.3, Cc Lang, Qd Wang, F Lu, Ki Clubb Jan 2010

The Radio Properties And Magnetic Field Configuration In The Crab-Like Pulsar Wind Nebula G54.1+0.3, Cc Lang, Qd Wang, F Lu, Ki Clubb

Astronomy Department Faculty Publication Series

We present a multifrequency radio investigation of the Crab-like pulsar wind nebula (PWN) G54.1+0.3 using the Very Large Array. The high resolution of the observations reveals that G54.1+0.3 has a complex radio structure which includes filamentary and loop-like structures that are magnetized, a diffuse extent similar to the associated diffuse X-ray emission. But the radio and X-ray structures in the central region differ strikingly, indicating that they trace very different forms of particle injection from the pulsar and/or particle acceleration in the nebula. No spectral index gradient is detected in the radio emission across the PWN, whereas the X-ray emission …

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X-Raying Galaxies: A Chandra Legacy, Qd Wang Jan 2010

X-Raying Galaxies: A Chandra Legacy, Qd Wang

Astronomy Department Faculty Publication Series

This presentation reviews Chandra’s major contribution to the understanding of nearby galaxies. After a brief summary on significant advances in characterizing various types of discrete x-ray sources, the presentation focuses on the global hot gas in and around galaxies, especially normal ones like our own. The hot gas is a product of stellar and active galactic nuclear feedback—the least understood part in theories of galaxy formation and evolution. Chandra observations have led to the first characterization of the spatial, thermal, chemical, and kinetic properties of the gas in our galaxy. The gas is concentrated around the galactic bulge and disk …

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Extinction Toward The Compact Hii Regions G-0.02-0.07, Ea Mills, Mr Morris, Cc Lang, A Cotera, H Dong, Qd Wang, Sr Stolovy Jan 2010

Extinction Toward The Compact Hii Regions G-0.02-0.07, Ea Mills, Mr Morris, Cc Lang, A Cotera, H Dong, Qd Wang, Sr Stolovy

Astronomy Department Faculty Publication Series

The four HII regions in the Sgr A East complex: A, B, C, and D, represent evidence of recent massive star formation in the central ten parsecs. Using Paschen-alpha images taken with HST and 8.4 GHz VLA data, we construct an extinction map of A-D, and briefly discuss their morphology and location.

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X-Ray Spectroscopy Of Galactic Hot Gas Along The Pks 2155$-$304 Sight Line, T Hagihara, Y Yao, Ny Yamasaki, K Mitsuda, Qd Wang, Y Takei, T Yoshino, D Mccammon Jan 2010

X-Ray Spectroscopy Of Galactic Hot Gas Along The Pks 2155$-$304 Sight Line, T Hagihara, Y Yao, Ny Yamasaki, K Mitsuda, Qd Wang, Y Takei, T Yoshino, D Mccammon

Astronomy Department Faculty Publication Series

We present a detailed spectroscopic study of the hot gas in the Galactic halo toward the direction of a blazer PKS 2155304 ( 0.117). The OVII and OVIII absorption lines were measured with the Low and High Energy Transmission Grating Spectrographs aboard Chandra, and the OVII, OVIII, and NeIX emission lines produced in an adjacent field of the PKS 2155304 direction were observed with the X-ray Imaging Spectrometer aboard Suzaku. Assuming vertically exponential distributions of the gas temperature and the density, we performed a combined analysis of the absorption and emission data. The gas temperature and the density at the …

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The Physical Scale Of The Far-Infrared Emission In The Most Luminous Submillimetre Galaxies – Ii. Evidence For Merger-Driven Star Formation, Jd Younger, Gg Fazio, Mln Ashby, F Civano, Ma Gurwell, J-S Huang, D Iono, Ab Peck, Gr Petitpas, Ks Scott, Dj Wilner, Gw Wilson, Min Yun Jan 2010

The Physical Scale Of The Far-Infrared Emission In The Most Luminous Submillimetre Galaxies – Ii. Evidence For Merger-Driven Star Formation, Jd Younger, Gg Fazio, Mln Ashby, F Civano, Ma Gurwell, J-S Huang, D Iono, Ab Peck, Gr Petitpas, Ks Scott, Dj Wilner, Gw Wilson, Min Yun

Astronomy Department Faculty Publication Series

We present high-resolution 345-GHz interferometric observations of two extremely luminous (Lir≳ 1013 L⊙), submillimetre-selected galaxies (SMGs) in the Cosmic Evolution Survey (COSMOS) field with the Submillimeter Array (SMA). Both targets were previously detected as unresolved point sources by the SMA in its compact configuration, also at 345 GHz. These new data, which provide a factor of ≳3 improvement in resolution, allow us to measure the physical scale of the far-infrared in the submillimetre directly. The visibility functions of both targets show significant evidence for structure on ∼0.5–1-arcsec scales, which at z≳ 1.5 translates …

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The Far-Infrared/Submillimeter Properties Of Galaxies Located Behind The Bullet Cluster, M Rex, Min Yun, Et. Al. Jan 2010

The Far-Infrared/Submillimeter Properties Of Galaxies Located Behind The Bullet Cluster, M Rex, Min Yun, Et. Al.

Astronomy Department Faculty Publication Series

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 …

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New Panoramic View Of $^{12}$Co And 1.1 Mm Continuum Emission In The Orion A Giant Molecular Cloud. I. Survey Overview And Possible External Triggers Of Star Formation, Y Shimajiri, R Kawabe, S Takakuwa, M Saito, T Tsukagoshi, M Momose, N Ikeda, E Akiyama, Je Austermann, H Ezawa, K Fukue, M Hiramatsu, D Hughes, Y Kitamura, K Kohno, Y Kurono, Ks Scott, Gw Wilson, A Yoshida, Min Yun Jan 2010

New Panoramic View Of $^{12}$Co And 1.1 Mm Continuum Emission In The Orion A Giant Molecular Cloud. I. Survey Overview And Possible External Triggers Of Star Formation, Y Shimajiri, R Kawabe, S Takakuwa, M Saito, T Tsukagoshi, M Momose, N Ikeda, E Akiyama, Je Austermann, H Ezawa, K Fukue, M Hiramatsu, D Hughes, Y Kitamura, K Kohno, Y Kurono, Ks Scott, Gw Wilson, A Yoshida, Min Yun

Astronomy Department Faculty Publication Series

We present new, wide, and deep images in the 1.1 mm continuum and the CO ( 1–0) emission toward the northern part of the Orion A Giant Molecular Cloud (Orion-A GMC). The 1.1 mm data were taken with the AzTEC camera mounted on the Atacama Submillimeter Telescope Experiment (ASTE) 10 m telescope in Chile, and the CO ( 1–0) data were with the 25 beam receiver (BEARS) on the Nobeyama Radio Observatory (NRO) 45 m telescope in the On-The-Fly (OTF) mode. The present AzTEC observations are the widest (17 23, corresponding to 12 pc 17 pc) and the highest-sensitivity (9 …

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Detection Of Diffuse Neutral Intragroup Medium In Hickson Compact Groups, S Borthakur, Min Yun, L Verdes-Montenegro Jan 2010

Detection Of Diffuse Neutral Intragroup Medium In Hickson Compact Groups, S Borthakur, Min Yun, L Verdes-Montenegro

Astronomy Department Faculty Publication Series

We present new Green Bank Telescope (GBT) 21 cm neutral hydrogen (H I) observations of a complete distance-limited sample of 22 Hickson Compact Groups (HCGs) with at least four true members. We detected an average H I mass of 8 × 109 M (median = 6 × 109 M ), which is significantly larger than previous single-dish measurements. Consequently, the H I deficiencies for these HCGs have been reduced, although not completely eliminated. Spectral comparison of the GBT data with complementary Very Large Array data shows significant H I excess in the GBT spectra. The observed excess is …

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Herschel Observations Of Ortho- And Para-Oxidaniumyl (H2o+) In Spiral Arm Clouds Toward Sagittarius B2(M) *,**, P Schilke, Nr Erickson, Et. Al. Jan 2010

Herschel Observations Of Ortho- And Para-Oxidaniumyl (H2o+) In Spiral Arm Clouds Toward Sagittarius B2(M) *,**, P Schilke, Nr Erickson, Et. Al.

Astronomy Department Faculty Publication Series

H2O+ has been observed in its ortho- and para- states toward the massive star forming core Sgr B2(M), located close to the Galactic center. The observations show absorption in all spiral arm clouds between the Sun and Sgr B2. The average o/p ratio of H2O+ in most velocity intervals is 4.8, which corresponds to a nuclear spin temperature of 21 K. The relationship of this spin temperature to the formation temperature and current physical temperature of the gas hosting H2O+ is discussed, but no firm conclusion is reached. In …

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A High-Resolution Line Survey Of Irc +10216 With Herschel/Hifi *,** First Results: Detection Of Warm Silicon Dicarbide (Sic), J Cernicharo, Lbfm Waters, L Decin, P Encrenaz, Aggm Tielens, M Agundez, E Debeck, Hsp Muller, Jr Goicoechea, Mj Barlow, A Benz, N Crimier, F Daniel, Am Digiorgio, M Fich, T Gaier, P Garcia-Lario, A Dekoter, T Khouri, R Liseau, R Lombaert, Nr Erickson, Jr Pardo, Jc Pearson, R Shipman, C Sanchez Contreras, D Teyssier Jan 2010

A High-Resolution Line Survey Of Irc +10216 With Herschel/Hifi *,** First Results: Detection Of Warm Silicon Dicarbide (Sic), J Cernicharo, Lbfm Waters, L Decin, P Encrenaz, Aggm Tielens, M Agundez, E Debeck, Hsp Muller, Jr Goicoechea, Mj Barlow, A Benz, N Crimier, F Daniel, Am Digiorgio, M Fich, T Gaier, P Garcia-Lario, A Dekoter, T Khouri, R Liseau, R Lombaert, Nr Erickson, Jr Pardo, Jc Pearson, R Shipman, C Sanchez Contreras, D Teyssier

Astronomy Department Faculty Publication Series

We present the first results of a high-spectral-resolution survey of the carbon-rich evolved star IRC+10216 that was carried out with the HIFI spectrometer onboard Herschel. This survey covers all HIFI bands, with a spectral range from 488 to 1901 GHz. In this letter we focus on the band-1b spectrum, in a spectral range 554.5–636.5 GHz, where we identified 130 spectral features with intensities above 0.03 K and a signal-to-noise ratio >5. Detected lines arise from HCN, SiO, SiS, CS, CO, metal-bearing species and, surprisingly, silicon dicarbide (SiC2). We identified 55 SiC2 transitions involving energy levels between …

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Deep 1.1 Mm-Wavelength Imaging Of The Goods-S Field By Aztec/Aste - I. Source Catalogue And Number Counts, Ks Scott, Min Yun, Gw Wilson, Je Austermann, E Aguilar, I Aretxaga, H Ezawa, D Ferrusca, B Hatsukade, Dh Hughes, D Iono, M Giavalisco, R Kawabe, K Kohno, Pd Mauskopf, T Oshima, Ta Perera, J Rand, Y Tamura, T Tosaki, M Velazquez, Cc Williams, M Zeballos Jan 2010

Deep 1.1 Mm-Wavelength Imaging Of The Goods-S Field By Aztec/Aste - I. Source Catalogue And Number Counts, Ks Scott, Min Yun, Gw Wilson, Je Austermann, E Aguilar, I Aretxaga, H Ezawa, D Ferrusca, B Hatsukade, Dh Hughes, D Iono, M Giavalisco, R Kawabe, K Kohno, Pd Mauskopf, T Oshima, Ta Perera, J Rand, Y Tamura, T Tosaki, M Velazquez, Cc Williams, M Zeballos

Astronomy Department Faculty Publication Series

We present the first results from a confusion-limited map of the Great Observatories Origins Deep Survey-South (GOODS-S) taken with the AzTEC camera on the Atacama Submillimeter Telescope Experiment. We imaged a field to a 1σ depth of 0.48–0.73 mJy beam−1, making this one of the deepest blank-field surveys at mm-wavelengths ever achieved. Although by traditional standards our GOODS-S map is extremely confused due to a sea of faint underlying sources, we demonstrate through simulations that our source identification and number counts analyses are robust, and the techniques discussed in this paper are relevant for other deeply confused surveys. …

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Westerbork Ultra-Deep Survey Of Hi At Z=0.2, M Verheijen, B Deshev, J Van Gorkom, B Poggianti, A Chung, R Cybulski, Ks Dawarakanath, M Montero-Castano, G Morrison, D Schiminovich, A Szomoru, Min Yun Jan 2010

Westerbork Ultra-Deep Survey Of Hi At Z=0.2, M Verheijen, B Deshev, J Van Gorkom, B Poggianti, A Chung, R Cybulski, Ks Dawarakanath, M Montero-Castano, G Morrison, D Schiminovich, A Szomoru, Min Yun

Astronomy Department Faculty Publication Series

In this contribution, we present some preliminary observational results from the completed ultra-deep survey of 21cm emission from neutral hydrogen at redshifts z=0.164-0.224 with the Westerbork Synthesis Radio Telescope. In two separate fields, a total of 160 individual galaxies has been detected in neutral hydrogen, with HI masses varying from 1.1x10^9 to 4.0x10^10 Msun. The largest galaxies are spatially resolved by the synthesized beam of 23x37 arcsec^2 while the velocity resolution of 19 km/s allowed the HI emission lines to be well resolved. The large scale structure in the surveyed volume is traced well in HI, apart from the highest …

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Spitzer Observations Of The Λ Orionis Cluster. Ii. Disks Around Solar-Type And Low-Mass Stars, Jesús Hernández, Maria Morales-Calderon, Nuria Calvet, L. Hartmann, J. Muzerolle, R. Gutermuth Jan 2010

Spitzer Observations Of The Λ Orionis Cluster. Ii. Disks Around Solar-Type And Low-Mass Stars, Jesús Hernández, Maria Morales-Calderon, Nuria Calvet, L. Hartmann, J. Muzerolle, R. Gutermuth

Astronomy Department Faculty Publication Series

We present IRAC/MIPS Spitzer Space Telescope observations of the solar-type and the low-mass stellar population of the young (~5 Myr) λ Orionis cluster. Combining optical and Two Micron All Sky Survey photometry, we identify 436 stars as probable members of the cluster. Given the distance (450 pc) and the age of the cluster, our sample ranges in mass from 2 M sun to objects below the substellar limit. With the addition of the Spitzer mid-infrared data, we have identified 49 stars bearing disks in the stellar cluster. Using spectral energy distribution slopes, we place objects in several classes: non-excess stars …

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The Mass Distribution Of Starless And Protostellar Cores In Gould Belt Clouds, Sarah I. Sadavoy, James Di Francesco, Sylvain Bontemps, S. Thomas Megeath, Luisa M. Rebull, Erin Allgaier, Sean Carey, Robert Gutermuth Jan 2010

The Mass Distribution Of Starless And Protostellar Cores In Gould Belt Clouds, Sarah I. Sadavoy, James Di Francesco, Sylvain Bontemps, S. Thomas Megeath, Luisa M. Rebull, Erin Allgaier, Sean Carey, Robert Gutermuth

Astronomy Department Faculty Publication Series

Using data from the SCUBA Legacy Catalogue (850 μm) and Spitzer Space Telescope (3.6-70 μm), we explore dense cores in the Ophiuchus, Taurus, Perseus, Serpens, and Orion molecular clouds. We develop a new method to discriminate submillimeter cores found by Submillimeter Common-User Bolometer Array (SCUBA) as starless or protostellar, using point source photometry from Spitzer wide field surveys. First, we identify infrared sources with red colors associated with embedded young stellar objects (YSOs). Second, we compare the positions of these YSO candidates to our submillimeter cores. With these identifications, we construct new, self-consistent starless and protostellar core mass functions (CMFs) …

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Total Infrared Luminosity Estimation Of Resolved And Unresolved Galaxies, M Boquien, G Bendo, D Calzetti, D Dale, C Engelbracht, R Kennicutt, Jc Lee, L Van Zee, J Moustakas Jan 2010

Total Infrared Luminosity Estimation Of Resolved And Unresolved Galaxies, M Boquien, G Bendo, D Calzetti, D Dale, C Engelbracht, R Kennicutt, Jc Lee, L Van Zee, J Moustakas

Astronomy Department Faculty Publication Series

The total infrared (TIR) luminosity from galaxies can be used to examine both star formation and dust physics. We provide here new relations to estimate the TIR luminosity from various Spitzer bands, in particular from the 8 μm and 24 μm bands. To do so, we use data for 45'' subregions within a subsample of nearby face-on spiral galaxies from the Spitzer Infrared Nearby Galaxies Survey (SINGS) that have known oxygen abundances as well as integrated galaxy data from the SINGS, the Local Volume Legacy survey (LVL), and Engelbracht et al. samples. Taking into account the oxygen abundances of the …

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A Spitzer View Of Star Formation In The Cygnus X North Complex, I. M. Beerer, X. P. Koenig, J. L. Hora, R. A. Gutermuth Jan 2010

A Spitzer View Of Star Formation In The Cygnus X North Complex, I. M. Beerer, X. P. Koenig, J. L. Hora, R. A. Gutermuth

Astronomy Department Faculty Publication Series

We present new images and photometry of the massive star-forming complex Cygnus X obtained with the Infrared Array Camera (IRAC) and the Multiband Imaging Photometer for Spitzer (MIPS) on board the Spitzer Space Telescope. A combination of IRAC, MIPS, UKIRT Deep Infrared Sky Survey, and Two Micron All Sky Survey data are used to identify and classify young stellar objects (YSOs). Of the 8231 sources detected exhibiting infrared excess in Cygnus X North, 670 are classified as class I and 7249 are classified as class II. Using spectra from the FAST Spectrograph at the Fred L. Whipple Observatory and Hectospec …

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The Morphology Of Passively Evolving Galaxies At Z ~ 2 From Hst/Wfc3 Deep Imagin In The Hubble Ultradeep Field, P Cassata, M Giavalisco, Yc Guo, H Ferguson, Am Koekemoer, A Renzini, A Fontana, S Salimbeni, M Dickinson, S Casertano, Cj Conselice, N Grogin, Jm Lotz, C Papovich, Ra Lucas, A Straughn, Jp Gardner, L Moustakas Jan 2010

The Morphology Of Passively Evolving Galaxies At Z ~ 2 From Hst/Wfc3 Deep Imagin In The Hubble Ultradeep Field, P Cassata, M Giavalisco, Yc Guo, H Ferguson, Am Koekemoer, A Renzini, A Fontana, S Salimbeni, M Dickinson, S Casertano, Cj Conselice, N Grogin, Jm Lotz, C Papovich, Ra Lucas, A Straughn, Jp Gardner, L Moustakas

Astronomy Department Faculty Publication Series

We present near–IR images, obtained with the Hubble Space Telescope (HST) and the WFC3/IR camera, of six passive and massive galaxies at redshift 1.3 < z < 2.4 (SSFR< 10−2 Gyr−1; stellar mass M ∼ 1011 M⊙), selected from the Great Observatories Origins Deep Survey (GOODS). These images, which have a spatial resolution of ∼ 1.5 kpc, provide the deepest view of the optical rest–frame morphology of such systems to date. We find that the light profile of these galaxies is regular and well described by a Sérsic model with index typical of today’s spheroids. Their size, however, …

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Evidence Of A Fast Evolution Of The Uv Luminosity Function Beyond Redshift 6 From A Deep Hawk-I Survey Of The Goods-S Field, M Castellano, A Fontana, K Boutsia, A Grazian, L Pentericci, R Bouwens, M Dickinson, M Giavalisco, P Santini, S Cristiani, Et. Al. Jan 2010

Evidence Of A Fast Evolution Of The Uv Luminosity Function Beyond Redshift 6 From A Deep Hawk-I Survey Of The Goods-S Field, M Castellano, A Fontana, K Boutsia, A Grazian, L Pentericci, R Bouwens, M Dickinson, M Giavalisco, P Santini, S Cristiani, Et. Al.

Astronomy Department Faculty Publication Series

No abstract provided.

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The Unusual N Iv]-Emitter Galaxy Gds J033218.92-275302.7: Star Formation Or Agn-Driven Winds From A Massive Galaxy At Z=5.56, E Vanzella, A Grazian, M Hayes, L Pentericci, D Schaerer, M Dickinson, S Cristiani, M Giavalisco, A Verhamme, M Nonino, P Rosati Jan 2010

The Unusual N Iv]-Emitter Galaxy Gds J033218.92-275302.7: Star Formation Or Agn-Driven Winds From A Massive Galaxy At Z=5.56, E Vanzella, A Grazian, M Hayes, L Pentericci, D Schaerer, M Dickinson, S Cristiani, M Giavalisco, A Verhamme, M Nonino, P Rosati

Astronomy Department Faculty Publication Series

Aims. We investigate the nature of the source GDS J033218.92-275302.7 at redshift 5.56.
Methods. The spectral energy distribution of the source is well-sampled by 16 bands photometry from UV-optical (HST and VLT), near infrared, near infrared (VLT) to mid-infrared (Spitzer). The detection of a signal in the mid-infrared Spitzer/IRAC bands 5.8, 8.0 - where the nebular emission contribution is less effective - suggests that there is a Balmer break, the signature of an underlying stellar population formed at earlier epochs. The high-quality VLT/FORS2 spectrum shows a clear Ly emission line, together with semi-forbidden N IV] 1483.3-1486.5 also …

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Pressure Support Versus Thermal Broadening In The Lyman Alpha Forest - I. Effects Of The Equation Of State On Longitudinal Structure, Ms Peeples, Dh Weinberg, R Dave, Ma Fardal, N Katz Jan 2010

Pressure Support Versus Thermal Broadening In The Lyman Alpha Forest - I. Effects Of The Equation Of State On Longitudinal Structure, Ms Peeples, Dh Weinberg, R Dave, Ma Fardal, N Katz

Astronomy Department Faculty Publication Series

In the low-density intergalactic medium that gives rise to the Lyman α (Lyα) forest, gas temperature and density are tightly correlated. The velocity scale of thermal broadening and the Hubble flow across the gas Jeans scale are of similar magnitude (HλJ∼σth). To separate the effects of gas pressure support and thermal broadening on the Lyα forest, we compare spectra extracted from two smoothed particle hydrodynamics simulations evolved with different photoionization heating rates (and thus different Jeans scales) and from the pressureless dark matter distribution, imposing different temperature–density relations on the evolved particle distributions. The …

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Aztec Half Square Degree Survey Of The Shades Fields - I. Maps, Catalogues And Source Counts, Je Austermann, Min Yun, Et. Al. Jan 2010

Aztec Half Square Degree Survey Of The Shades Fields - I. Maps, Catalogues And Source Counts, Je Austermann, Min Yun, Et. Al.

Astronomy Department Faculty Publication Series

We present the first results from the largest deep extragalactic mm-wavelength survey undertaken to date. These results are derived from maps covering over 0.7 deg2, made at λ= 1.1 mm, using the AzTEC continuum camera mounted on the James Clerk Maxwell Telescope. The maps were made in the two fields originally targeted at λ= 850 μm with the Submillimetre Common-User Bolometer Array (SCUBA) in the SCUBA Half-Degree Extragalactic Survey (SHADES) project, namely the Lockman Hole East (mapped to a depth of 0.9–1.3 mJy rms) and the Subaru/XMM–Newton Deep Field (mapped to a depth of 1.0–1.7 mJy rms). …

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Hst Palpha Survey Of The Galactic Center -- Searching The Missing Young Stellar Populations Within The Galactic Center, H Dong, Qd Wang, A Cortera, S Stolovy, Mr Morris, J Mauerhan, Ea Mills, G Schneider, C Lang Jan 2010

Hst Palpha Survey Of The Galactic Center -- Searching The Missing Young Stellar Populations Within The Galactic Center, H Dong, Qd Wang, A Cortera, S Stolovy, Mr Morris, J Mauerhan, Ea Mills, G Schneider, C Lang

Astronomy Department Faculty Publication Series

No abstract provided.

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Aztec/Aste 1.1-Mm Survey Of The Akari Deep Field South: Source Catalogue And Number Counts, B Hatsukade, K Kohno, I Aretxaga, Je Austermann, H Ezawa, Dh Hughes, S Ikarashi, D Iono, R Kawabe, S Khan, H Matsuo, S Matsuura, K Nakanishi, T Oshima, T Perera, Ks Scott, M Shirahata, Tt Takeuchi, Y Yamura, K Tanaka, T Tosaki, Gw Wilson, Min Yun Jan 2010

Aztec/Aste 1.1-Mm Survey Of The Akari Deep Field South: Source Catalogue And Number Counts, B Hatsukade, K Kohno, I Aretxaga, Je Austermann, H Ezawa, Dh Hughes, S Ikarashi, D Iono, R Kawabe, S Khan, H Matsuo, S Matsuura, K Nakanishi, T Oshima, T Perera, Ks Scott, M Shirahata, Tt Takeuchi, Y Yamura, K Tanaka, T Tosaki, Gw Wilson, Min Yun

Astronomy Department Faculty Publication Series

We present results of a 1.1-mm deep survey of the AKARI Deep Field South (ADF-S) with AzTEC mounted on the Atacama Submillimetre Telescope Experiment (ASTE). We obtained a map of 0.25-deg2 area with an rms noise level of 0.32–0.71 mJy. This is one of the deepest and widest maps thus far at millimetre and submillimetre wavelengths. We uncovered 198 sources with a significance of 3.5σ–15.6σ, providing the largest catalogue of 1.1-mm sources in a contiguous region. Most of the sources are not detected in the far-infrared bands of the AKARI satellite, suggesting that they are mostly at z≥ …

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Setting The Normalcy Level Of Hi Properties In Isolated Galaxies, D Espada, L Verdes-Montenegro, E Athanassoula, A Bosma, Wk Huchtmeier, S Leon, U Lisenfeld, J Sabater, J Sulentic, S Verley, Min Yun Jan 2010

Setting The Normalcy Level Of Hi Properties In Isolated Galaxies, D Espada, L Verdes-Montenegro, E Athanassoula, A Bosma, Wk Huchtmeier, S Leon, U Lisenfeld, J Sabater, J Sulentic, S Verley, Min Yun

Astronomy Department Faculty Publication Series

Studying the atomic gas (HI) properties of the most isolated galaxies is essential to quantify the effect that the environment exerts on this sensitive component of the interstellar medium. We observed and compiled HI data for a well defined sample of ∼ 800 galaxies in the Catalog of Isolated Galaxies, as part of the AMIGA project (Analysis of the ISM in Isolated GAlaxies, http://amiga.iaa.es), which enlarges considerably previous samples used to quantify the HI deficiency in galaxies located in denser environments. By studying the shape of 182 HI profiles, we revisited the usually accepted result that, independently of the environment, …

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Submillimeter Array Identification Of The Millimeter-Selected Galaxy Ssa22-Aztec1: A Protoquasar In A Protocluster?, Y Tamura, D Iono, Dj Wilner, M Kajisawa, Yk Uchimoto, Dm Alexander, A Chung, H Ezawa, B Hatsukade, T Hayashino, Dh Hughes, T Ichikawa, S Irkarashi, R Kawabe, K Kohno, Bd Lehmer, Y Matsuda, K Nakanishi, T Takata, Gw Wilson, T Yamada, Min Yun Jan 2010

Submillimeter Array Identification Of The Millimeter-Selected Galaxy Ssa22-Aztec1: A Protoquasar In A Protocluster?, Y Tamura, D Iono, Dj Wilner, M Kajisawa, Yk Uchimoto, Dm Alexander, A Chung, H Ezawa, B Hatsukade, T Hayashino, Dh Hughes, T Ichikawa, S Irkarashi, R Kawabe, K Kohno, Bd Lehmer, Y Matsuda, K Nakanishi, T Takata, Gw Wilson, T Yamada, Min Yun

Astronomy Department Faculty Publication Series

We present results from Submillimeter Array (SMA) 860 μm subarcsecond astrometry and multiwavelength observations of the brightest millimeter (S 1.1mm = 8.4 mJy) source, SSA22-AzTEC1, found near the core of the SSA22 protocluster that is traced by Lyα-emitting galaxies at z = 3.09. We identify a 860 μm counterpart with a flux density of S 860 μm = 12.2 ± 2.3 mJy and absolute positional accuracy that is better than 03. At the SMA position, we find radio-to-mid-infrared counterparts, whilst no object is found in Subaru optical and near-infrared deep images at wavelengths ≤1 μm (J > 25.4 in …

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