Search Publications
A Comparison of Reconstruction Methods for the Estimation of Coronal Mass Ejections Kinematics Based on SECCHI/HI Observations
Srivastava, Nandita; Mishra, Wageesh; Davies, Jackie A.
A study of the kinematics and arrival times of coronal mass ejections (CMEs) at Earth, derived from time-elongation maps (J-maps) constructed from STEREO/heliospheric imager (HI) observations, provides an opportunity to understand the heliospheric evolution of CMEs in general. We implement various reconstruction techniques, based on the use of tim…
Delving Into X-ray Obscuration of Type 2 AGN, Near and Far
Heckman, Timothy M.; Gandhi, Poshak; Yaqoob, Tahir +4 more
Using self-consistent, physically motivated models, we investigate the X-ray obscuration in 19 Type 2 [O III] 5007 Å selected active galactic nuclei (AGNs), 9 of which are local Seyfert 2 galaxies and 10 of which are Type 2 quasar candidates. We derive reliable line-of-sight and global column densities for these objects, which is the first time th…
Probing the Large and Massive Circumgalactic Medium of a Galaxy at z ~ 0.2 using a Pair of Quasars
Muzahid, Sowgat
We present an analysis of two O VI absorbers at redshift z abs = 0.227, which were detected in the spectra of two closely spaced QSO sightlines (Q 0107-025A and B) and observed with the Cosmic Origins Spectrograph onboard the Hubble Space Telescope. At the same redshift, the presence of a single bright (~1.2L sstarf) galaxy a…
Interferometric Follow-up of WISE Hyper-luminous Hot, Dust-obscured Galaxies
Tsai, Chao-Wei; Gelino, Christopher R.; Wright, Edward L. +10 more
The Wide-field Infrared Survey Explorer (WISE) has discovered an extraordinary population of hyper-luminous dusty galaxies that are faint in the two bluer passbands (3.4 µm and 4.6 µm) but are bright in the two redder passbands of WISE (12 µm and 22 µm). We report on initial follow-up observations of three of these hot, dus…
Halo Mass Dependence of H I and O VI Absorption: Evidence for Differential Kinematics
Kacprzak, Glenn G.; Churchill, Christopher W.; Nielsen, Nikole M. +4 more
We studied a sample of 14 galaxies (0.1 < z < 0.7) using HST/WFPC2 imaging and high-resolution HST/COS or HST/STIS quasar spectroscopy of Lyα, Lyβ, and O VI λλ1031, 1037 absorption. The galaxies, having 10.8 <= log (M h/M ⊙) <= 12.2, lie within D = 300 kpc of quasar sightlines, probing out to D/R vir =…
HerMES: Spectral Energy Distributions of Submillimeter Galaxies at z > 4
Bock, J. J.; Clements, D. L.; Burgarella, D. +20 more
We present a study of the infrared properties for a sample of seven spectroscopically confirmed submillimeter galaxies (SMGs) at z > 4.0. By combining ground-based near-infrared, Spitzer IRAC and MIPS, Herschel SPIRE, and ground-based submillimeter/millimeter photometry, we construct their spectral energy distributions (SEDs) and a composite mo…
The NUV-r versus Mr Plane as a Tracer of Early-type Galaxy Evolution in the USGC U376 and LGG 225 Groups
Mazzei, Paola; Rampazzo, Roberto; Marino, Antonietta
With the aim of tracing back the evolution of galaxies in nearby groups, we use smooth particle hydrodynamical (SPH) simulations with chemo-photometric implementation. Here, we focus on the evolution of the early-type members (Es and S0s; ETGs hereafter) in two groups, USGC U376 and LGG 225, both in the Leo cloud. We use the near-UV (NUV)-optical …
Fermi-LAT Observations of Supernova Remnants Kesteven 79
Auchettl, Katie; Slane, Patrick; Castro, Daniel
In this paper, we report on the detection of γ-ray emission coincident with the Galactic supernova remnant (SNR) Kesteven 79 (Kes 79). We analyzed approximately 52 months of data obtained with the Large Area Telescope on board the Fermi Gamma-ray Space Telescope. Kes 79 is thought to be interacting with adjacent molecular clouds, based on the pres…
Accounting for Cosmic Variance in Studies of Gravitationally Lensed High-redshift Galaxies in the Hubble Frontier Field Clusters
Ellis, Richard S.; Robertson, Brant E.; Dunlop, James S. +3 more
Strong gravitational lensing provides a powerful means for studying faint galaxies in the distant universe. By magnifying the apparent brightness of background sources, massive clusters enable the detection of galaxies fainter than the usual sensitivity limit for blank fields. However, this gain in effective sensitivity comes at the cost of a redu…
Can Charge Exchange Explain Anomalous Soft X-Ray Emission in the Cygnus Loop?
Wu, Y.; Shelton, R. L.; Henley, D. B. +4 more
Recent X-ray studies have shown that supernova shock models are unable to satisfactorily explain X-ray emission in the rim of the Cygnus Loop. In an attempt to account for this "anomalously" enhanced X-ray flux, we fit the region with a model including theoretical charge exchange (CX) data along with shock and background X-ray models. The model in…