Search Publications
Metallicity and Physical Conditions in the Magellanic Bridge
Keenan, F. P.; Smoker, J. V.; Lehner, N. +1 more
We present a new analysis of the diffuse gas in the Magellanic Bridge (R.A. gtrsim 3h) based on HST STIS E140M and FUSE spectra of two early-type stars lying within the Bridge and a QSO behind it. We derive the column densities of the H I (from Lyα), N I, O I, Ar I, Si II, S II, and Fe II of the gas in the Bridge. Using the atomic speci…
The Environment of M85 Optical Transient 2006-1: Constraints on the Progenitor Age and Mass
Cenko, S. B.; Kulkarni, S. R.; Ferrarese, L. +11 more
M85 Optical Transient 2006-1 (M85 OT 2006-1) is the most luminous member of the small family of V838 Mon-like objects, whose nature is still a mystery. This event took place in the Virgo Cluster of galaxies and peaked at an absolute magnitude of MI ≈ - 13. Here we present Hubble Space Telescope images of M85 OT 2006-1 and its environmen…
The (Re-)Discovery of G350.1-0.3: A Young, Luminous Supernova Remnant and Its Neutron Star
Camilo, F.; Miller, J. M.; Gaensler, B. M. +6 more
We present an XMM-Newton observation of the long-overlooked radio source G350.1-0.3. The X-ray spectrum of G350.1-0.3 can be fit by a shocked plasma with two components: a high-temperature (1.5 keV) region with a low ionization timescale and enhanced abundances, plus a cooler (0.36 keV) component in ionization equilibrium and with solar abundances…
Color Profiles of Disk Galaxies since z ~ 1: Probing Outer Disk Formation Scenarios
Beckman, J. E.; Trujillo, I.; Azzollini, R.
We present deep color profiles for a sample of 415 disk galaxies within the redshift range 0.1 < z <= 1.1, and contained in HST ACS imaging of the GOODS-South field. For each galaxy, passband combinations are chosen to obtain, at each redshift, the best possible approximation to the rest-frame u - g color. We find that objects which show a t…
GRB 070201: A Possible Soft Gamma-Ray Repeater in M31
Cenko, S. B.; Stiele, H.; Pietsch, W. +13 more
GRB 070201 was a bright, short-duration, hard-spectrum gamma-ray burst detected by the Interplanetary Network. Its error quadrilateral, which has an area of 0.124 deg2, intersects some prominent spiral arms of the nearby M31 (Andromeda) galaxy. Given the properties of this GRB, along with the fact that LIGO data argue against a compact …
The Late Stellar Assembly of Massive Cluster Galaxies via Major Merging
Tran, Kim-Vy H.; Moustakas, John; Gonzalez, Anthony H. +3 more
We present multiwavelength observations of the brightest galaxies in four X-ray-luminous groups at z ~ 0.37 that will merge to form a cluster comparable in mass to Coma. Ordered by increasing stellar mass, the four brightest group galaxies (BGGs) present a time sequence where BGG-1, 2, and 3 are in merging systems and BGG-4 is a massive remnant (M…
The Off-Disk Thermal Structure of a Polar Coronal Hole
Landi, Enrico
The thermal structure of the coronal portion of coronal holes is a key factor in the modeling of the source regions and acceleration mechanisms of the fast solar wind. Studies aimed at this region are best carried out on observations outside the disk, where the chromosphere and transition region are not included in the line of sight. In the past, …
Stratification of Sunspot Umbral Dots from Inversion of Stokes Profiles Recorded by Hinode
Solanki, S. K.; Lagg, A.; Riethmüller, T. L.
This work aims to constrain the physical nature of umbral dots (UDs) using high-resolution spectropolarimetry. Full Stokes spectra recorded by the spectropolarimeter on Hinode of 51 UDs in a sunspot close to the disk center are analyzed. The height dependence of the temperature, magnetic field vector, and line-of-sight velocity across each UD is o…
Discovery of a Very Highly Extinguished Supernova in a Luminous Infrared Galaxy
Colina, L.; Kankare, E.; Efstathiou, A. +9 more
We report the discovery of a confirmed supernova (SN) and a supernova candidate in near-infrared images from the ALTAIR/NIRI adaptive optics system on the Gemini-North Telescope and NICMOS on the Hubble Space Telescope. The Gemini images were obtained as part of a near-infrared K-band search for highly obscured SNe in the nuclear regions of lumino…
The Extragalactic Distance Scale without Cepheids
Sakai, Shoko; Mould, Jeremy
Distances of galaxies in the Hubble Space Telescope Key Project are based on the Cepheid period-luminosity relation. An alternative basis is the tip of the red giant branch. Using archival HST data, we calibrate the infrared Tully-Fisher relation using 14 galaxies with tip of the red giant branch measurements. Compared with the Key Project, a high…