Science Archives Publication System

On the Significance of Absorption Features in HST/COS Data

DOI: 10.1086/667392 Bibcode: 2012PASP..124..830K

Danforth, Charles W.; France, Kevin; Stocke, John T. +2 more

We present empirical scaling relations for the significance of absorption features detected in medium-resolution, far-UV spectra obtained with the Cosmic Origins Spectrograph (COS). These relations properly account for both the extended wings of the COS line-spread function and the non-Poissonian noise properties of the data, which we characterize…

2012 • Publications of the Astronomical Society of the Pacific

eHST 43

Warm Gas in the Virgo Cluster. I. Distribution of Lyα Absorbers

DOI: 10.1088/0004-637X/754/2/84 Bibcode: 2012ApJ...754...84Y

Chen, Hsiao-Wen; Yoon, Joo Heon; Putman, Mary E. +2 more

The first systematic study of the warm gas (T = 10^{4 - 5} K) distribution across a galaxy cluster is presented using multiple background QSOs in and around the Virgo Cluster. We detect 25 Lyα absorbers (N_{H I} = 10^13.1-15.4 cm^-2) in the Virgo velocity range toward 9 of 12 QSO sightlines observed with the Co…

2012 • The Astrophysical Journal

eHST 43

The Star Formation History of M32

DOI: 10.1088/0004-637X/745/1/97 Bibcode: 2012ApJ...745...97M

Monachesi, Antonela; Lauer, Tod R.; Dressler, Alan +5 more

We use deep Hubble Space Telescope Advanced Camera for Surveys/High Resolution Channel observations of a field within M32 (F1) and an M31 background field (F2) to determine the star formation history (SFH) of M32 from its resolved stellar population. We find that 2-5 Gyr old stars contribute ~40% ± 17% of M32's mass, while ~55% ± 21% of M32's mass…

2012 • The Astrophysical Journal

eHST 43

CLASH: Discovery of a Bright z ~= 6.2 Dwarf Galaxy Quadruply Lensed by MACS J0329.6-0211

DOI: 10.1088/2041-8205/747/1/L9 Bibcode: 2012ApJ...747L...9Z

Shu, X.; Zheng, W.; Molino, A. +22 more

We report the discovery of a z _phot = 6.18^+0.05 _{- 0.07} (95% confidence level) dwarf galaxy, lensed into four images by the galaxy cluster MACS J0329.6-0211 (z_l = 0.45). The galaxy is observed as a high-redshift dropout in HST/ACS/WFC3 CLASH and Spitzer/IRAC imaging. Its redshift is securely determined du…

2012 • The Astrophysical Journal

eHST 43

Weak-lensing Results for the Merging Cluster A1758

DOI: 10.1088/0004-637X/744/2/94 Bibcode: 2012ApJ...744...94R

Bradač, M.; Markevitch, M.; Gonzalez, A. H. +2 more

Here we present the weak-lensing results for A1758, which is known to consist of four subclusters undergoing two separate mergers, A1758N and A1758S. Weak-lensing results for A1758N agree with previous weak-lensing results for clusters 1E0657-558 (Bullet cluster) and MACS J0025.4-1222, whose X-ray gas components were found to be largely separated …

2012 • The Astrophysical Journal

eHST 43

Discovery of VHE emission towards the Carina arm region with the H.E.S.S. telescope array: HESS J1018-589

DOI: 10.1051/0004-6361/201218843 Bibcode: 2012A&A...541A...5H

Klochkov, D.; Santangelo, A.; Quirrenbach, A. +191 more

The Carina arm region, containing the supernova remnant SNR G284.3-1.8, the high-energy (HE; E > 100 MeV) binary 1FGL J1018.6-5856 and the energetic pulsar PSR J1016-5857 and its nebula, has been observed with the H.E.S.S. telescope array. The observational coverage of the region in very-high-energy (VHE; E > 0.1 TeV) γ-rays benefits from de…

2012 • Astronomy and Astrophysics

XMM-Newton 43

Sizing up Partially Depleted Galaxy Cores

DOI: 10.1088/0004-637X/755/2/163 Bibcode: 2012ApJ...755..163D

Graham, Alister W.; Dullo, Bililign T.

We have modeled the inner surface brightness profiles of 39 alleged "core" galaxies with the core-Sérsic model, and provide new physical parameters for the largest ever sample of "core" galaxies fit with this model. When present, additional nuclear components were simultaneously modeled and the typical root-mean-square scatter of the fits (out to …

2012 • The Astrophysical Journal

eHST 43

The Stellar and Gas Kinematics of the LITTLE THINGS Dwarf Irregular Galaxy NGC 1569

DOI: 10.1088/0004-6256/144/5/152 Bibcode: 2012AJ....144..152J

Brinks, Elias; Hunter, Deidre A.; Johnson, Megan +5 more

In order to understand the formation and evolution of Magellanic-type dwarf irregular (dIm) galaxies, one needs to understand their three-dimensional structure. We present measurements of the stellar velocity dispersion in NGC 1569, a nearby post-starburst dIm galaxy. The stellar vertical velocity dispersion, σ_z, coupled with the maximu…

2012 • The Astronomical Journal

eHST 43

A unique isolated dwarf spheroidal galaxy at D = 1.9 Mpc

DOI: 10.1111/j.1365-2966.2012.21581.x Bibcode: 2012MNRAS.425..709M

Makarova, Lidia; Guhathakurta, Puragra; Makarov, Dmitry +5 more

We present a photometric and spectroscopic study of the unique isolated nearby dwarf spheroidal (dSph) galaxy KKR 25. The galaxy was resolved into stars with Hubble Space Telescope/Wide Field Planetary Camera 2 including old red giant branch and red clump. We have constructed a model of the resolved stellar populations and measured the star format…

2012 • Monthly Notices of the Royal Astronomical Society

eHST 43

Dust-to-gas Ratio in the Extremely Metal-poor Galaxy I Zw 18

DOI: 10.1088/0004-637X/752/2/112 Bibcode: 2012ApJ...752..112H

Cannon, John M.; Bolatto, Alberto D.; Leroy, Adam K. +7 more

The blue compact dwarf galaxy I Zw 18 is one of the most metal-poor systems known in the local universe (12+log(O/H) = 7.17). In this work we study I Zw 18 using data from Spitzer, Herschel Space Telescope, and IRAM Plateau de Bure Interferometer. Our data set includes the most sensitive maps of I Zw 18, to date, in both the far-infrared and the C…

2012 • The Astrophysical Journal

Herschel 43