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G 10.472+0.027: An Extreme Water Maser Outflow Associated with a Massive Protostellar Cluster
Ellingsen, S. P.; Voronkov, M. A.; Breen, S. L. +2 more
An Australia Telescope Compact Array search for 22 GHz water masers toward 6.7 GHz class II methanol masers detected in the Methanol Multibeam survey has resulted in the detection of extremely high-velocity emission from one of the sources. The water maser emission associated with this young stellar object covers a velocity span of nearly 300 km s…
Globular Cluster Scale Sizes in Giant Galaxies: The Case of M87 and the Role of Orbital Anisotropy and Tidal Filling
Sills, Alison; Harris, William E.; Webb, Jeremy J.
We present new Hubble Space Telescope imaging of the outer regions of M87 in order to study its globular cluster (GC) population out to large galactocentric distances. We discuss, particularly, the relationship between GC effective radii rh and projected galactocentric distance R gc. The observations suggest a shallow trend r…
Serendipitous Discovery of a Massive cD Galaxy at z = 1.096: Implications for the Early Formation and Late Evolution of cD Galaxies
Barro, Guillermo; Grogin, Norman A.; Hathi, Nimish P. +18 more
We have made a serendipitous discovery of a massive (~5 × 1011 M ⊙) cD galaxy at z = 1.096 in a candidate-rich cluster in the Hubble Ultra Deep Field (HUDF) area of GOODS-South. This brightest cluster galaxy (BCG) is the most distant cD galaxy confirmed to date. Ultra-deep HST/WFC3 images reveal an extended envelope starting …
Timescales on which Star Formation Affects the Neutral Interstellar Medium
Dolphin, Andrew E.; Williams, Benjamin F.; Ott, Jürgen +5 more
Turbulent neutral hydrogen (H I) line widths are often thought to be driven primarily by star formation (SF), but the timescale for converting SF energy to H I kinetic energy is unclear. As a complication, studies on the connection between H I line widths and SF in external galaxies often use broadband tracers for the SF rate, which must implicitl…
Uncovering Drivers of Disk Assembly: Bulgeless Galaxies and the Stellar Mass Tully-Fisher Relation
Ellis, Richard S.; Miller, Sarah H.; Sullivan, Mark
In order to determine what processes govern the assembly history of galaxies with rotating disks, we examine the stellar mass Tully-Fisher (TF) relation over a wide range in redshift partitioned according to whether or not galaxies contain a prominent bulge. Using our earlier Keck spectroscopic sample, for which bulge/total parameters are availabl…
Under Pressure: Star Clusters and the Neutral Hydrogen Medium of Tidal Tails
Bastian, N.; Konstantopoulos, I. S.; English, J. +9 more
Using archival data from ATCA, WHISP, and the Very Large Array, we have analyzed the H I emission of 22 tidal tail regions of the Mullan et al. sample of pairwise interacting galaxies. We have measured the column densities, line-of-sight velocity dispersions, and kinetic energy densities on ~kpc scales. We also constructed a tracer of the line-of-…
Multi-epoch Observations of the Red Wing Excess in the Spectrum of 3C 279
Punsly, Brian
It has been previously determined that there is a highly significant correlation between the spectral index from 10 GHz to 1350 Å and the amount of excess luminosity in the red wing of quasar C IV λ1549 broad emission lines (BELs). Ostensibly, the prominence of the red excess is associated with the radio jet emission mechanism and is most pronounc…
Dusty OB Stars in the Small Magellanic Cloud. II. Extragalactic Disks or Examples of the Pleiades Phenomenon?
Sandstrom, Karin M.; Bolatto, Alberto D.; Simon, Joshua D. +6 more
We use mid-infrared Spitzer spectroscopy and far-infrared Herschel photometry for a sample of 20 main sequence O9-B2 stars in the Small Magellanic Cloud (SMC) with strong 24 µm excesses to investigate the origin of the mid-IR emission. Either debris disks around the stars or illuminated patches of dense interstellar medium (ISM) can cause su…
UM 625 Revisited: Multiwavelength Study of a Seyfert 1 Galaxy with a Low-mass Black Hole
Ho, Luis C.; Jiang, Ning; Dong, Xiao-Bo +2 more
UM 625, previously identified as a narrow-line active galactic nucleus (AGN), actually exhibits broad Hα and Hβ lines whose width and luminosity indicate a low black hole (BH) mass of 1.6 × 106 M ⊙. We present a detailed multiwavelength study of the nuclear and host galaxy properties of UM 625. Analysis of Chandra and XMM-New…
Possible Detection of a Cyclotron Resonance Scattering Feature in the X-Ray Pulsar 4U 1909+07
Paul, Biswajit; Naik, Sachindra; Jaisawal, Gaurava K.
We present timing and broad band spectral studies of the high-mass X-ray binary pulsar 4U 1909+07 using data from Suzaku observations during 2010 November 2-3. The pulse period of the pulsar is estimated to be 604.11 ± 0.14 s. Pulsations are seen in the X-ray light curve up to ~70 keV. The pulse profile is found to be strongly energy-dependent: a …