Search Publications
Modeling the HD 32297 Debris Disk with Far-infrared Herschel Data
Krivov, A. V.; Augereau, J. -C.; Lebreton, J. +2 more
HD 32297 is a young A-star (~30 Myr) 112 pc away with a bright edge-on debris disk that has been resolved in scattered light. We observed the HD 32297 debris disk in the far-infrared and sub-millimeter with the Herschel Space Observatory PACS and SPIRE instruments, populating the spectral energy distribution (SED) from 63 to 500 µm. We aimed…
The Herschel DIGIT Survey of Weak-line T Tauri Stars: Implications for Disk Evolution and Dissipation
Henning, Thomas; Güdel, Manuel; Pinte, Christophe +8 more
As part of the "Dust, Ice, and Gas In Time (DIGIT)" Herschel Open Time Key Program, we present Herschel photometry (at 70, 160, 250, 350, and 500 µm) of 31 weak-line T Tauri star (WTTS) candidates in order to investigate the evolutionary status of their circumstellar disks. Of the stars in our sample, 13 had circumstellar disks previously kn…
High-resolution Study of the Cluster Complexes in a Lensed Spiral at Redshift 1.5: Constraints on the Bulge Formation and Disk Evolution
Östlin, G.; Bastian, N.; Zackrisson, E. +3 more
We analyze the clump population of the spiral galaxy Sp 1149 at redshift 1.5. Located behind the galaxy cluster MACS J1149.5+2223, Sp 1149 has been significantly magnified allowing us to study the galaxy on physical scales down to ~100 pc. The galaxy cluster frame is among the targets of the Cluster Lensing And Supernova survey with Hubble (CLASH)…
Young Stars near Earth: The Octans-Near Association and Castor Moving Group
Zuckerman, B.; Song, Inseok; Schneider, Adam +1 more
All cataloged stellar moving groups and associations with ages <=100 Myr and within 100 pc of Earth have Galactic space motions (UVW) situated in a "good box" with dimensions ~20 km s-1 on a side. Torres et al. defined the Octans Association as a group of 15 stars with age "20 Myr?" and located ~140 pc from Earth, but with average V …
Helioseismology of Pre-emerging Active Regions. II. Average Emergence Properties
Leka, K. D.; Barnes, G.; Birch, A. C. +2 more
We report on average subsurface properties of pre-emerging active regions as compared to areas where no active region emergence was detected. Helioseismic holography is applied to samples of the two populations (pre-emergence and without emergence), each sample having over 100 members, which were selected to minimize systematic bias, as described …
Environmental Effects in the Interaction and Merging of Galaxies in zCOSMOS
Kneib, J. -P.; Cimatti, A.; Sargent, M. T. +56 more
We analyze the environments and galactic properties (morphologies and star formation histories) of a sample of 153 close kinematic pairs in the redshift range 0.2 < z < 1 identified in the zCOSMOS-bright 10 k spectroscopic sample of galaxies. Correcting for projection effects, the fraction of close kinematic pairs is three times higher in th…
Concurrent Supermassive Black Hole and Galaxy Growth: Linking Environment and Nuclear Activity in z = 2.23 Hα Emitters
Lehmer, B. D.; Hornschemeier, A. E.; Smail, Ian +9 more
We present results from a ≈100 ks Chandra observation of the 2QZ Cluster 1004+00 structure at z = 2.23 (hereafter 2QZ Clus). 2QZ Clus was originally identified as an overdensity of four optically-selected QSOs at z = 2.23 within a 15 × 15 arcmin2 region. Narrow-band imaging in the near-IR (within the K band) revealed that the structure …
Fomalhaut b: Independent Analysis of the Hubble Space Telescope Public Archive Data
Macintosh, Bruce; Zuckerman, B.; Marois, Christian +1 more
The nature and even the existence of a putative planet-mass companion ("Fomalhaut b") to Fomalhaut has been debated since 2008. In the present paper, we reanalyze the multi-epoch ACS/STIS/WFC3 Hubble Space Telescope (HST) optical/near-infrared images on which the discovery and some other claims were based. We confirm that the HST images do reveal …
Revisiting Putative Cool Accretion Disks in Ultraluminous X-Ray Sources
Fabian, A. C.; Miller, J. M.; Reis, R. C. +4 more
Soft, potentially thermal spectral components observed in some ultra-luminous X-ray sources (ULXs) can be fit with models for emission from cool, optically thick accretion disks. If that description is correct, the low temperatures that are observed imply accretion onto "intermediate-mass" black holes. Subsequent work has found that these componen…
Ultra-Deep Hubble Space Telescope Imaging of the Small Magellanic Cloud: The Initial Mass Function of Stars with M <~ 1 M ⊙
Anderson, Jay; Dotter, Aaron; Rich, R. Michael +7 more
We present a new measurement of the stellar initial mass function (IMF) based on ultra-deep, high-resolution photometry of >5000 stars in the outskirts of the Small Magellanic Cloud (SMC) galaxy. The Hubble Space Telescope (HST) Advanced Camera for Surveys observations reveal this rich, cospatial population behind the foreground globular cluste…