Search Publications
Evidence for a Systematic Offset of -0.25 mas in the Gaia DR1 Parallaxes
Torres, Guillermo; Stassun, Keivan G.
We test the parallaxes reported in the Gaia first data release using the sample of eclipsing binaries with accurate, empirical distances from Stassun & Torres. We find an average offset of -0.25 ± 0.05 mas in the sense of the Gaia parallaxes being too small (I.e., the distances too long). The offset does not depend strongly on obvious paramete…
Lyman Continuum Escape Fraction of Star-forming Dwarf Galaxies at z ∼ 1
Teplitz, Harry I.; Rutkowski, Michael J.; Scarlata, Claudia +10 more
To date, no direct detection of Lyman continuum emission has been measured for intermediate-redshift (z∼ 1) star-forming galaxies. We combine Hubble Space Telescope grism spectroscopy with GALEX UV and ground-based optical imaging to extend the search for escaping Lyman continuum to a large (∼600) sample of z∼ 1 low-mass ({log}(\bar{M}) ≃ 9.3{M}
The Afterglow and Early-type Host Galaxy of the Short GRB 150101B at z = 0.1343
Berger, E.; Smith, N.; Zaritsky, D. +14 more
We present the discovery of the X-ray and optical afterglows of the short-duration GRB 150101B, pinpointing the event to an early-type host galaxy at z = 0.1343 ± 0.0030. This makes GRB 150101B the most nearby short gamma-ray burst (GRB) with an early-type host galaxy discovered to date. Fitting the spectral energy distribution of the host galaxy …
An Ultraviolet Spectrum of the Tidal Disruption Flare ASASSN-14li
Fruchter, Andrew S.; Filippenko, Alexei V.; Ramirez-Ruiz, Enrico +18 more
We present a Hubble Space Telescope Space Telescope Imaging Spectrograph spectrum of ASASSN-14li, the first rest-frame ultraviolet (UV) spectrum of a tidal disruption flare (TDF). The underlying continuum is well fit by a blackbody with {T}{UV}=3.5× {10}4 K, an order of magnitude smaller than the temperature inferred from X-r…
Evolution of Thermally Pulsing Asymptotic Giant Branch Stars. V. Constraining the Mass Loss and Lifetimes of Intermediate-mass, Low-metallicity AGB Stars
Williams, Benjamin F.; Dolphin, Andrew; Girardi, Léo +4 more
Thermally pulsing asymptotic giant branch (TP-AGB) stars are relatively short lived (less than a few Myr), yet their cool effective temperatures, high luminosities, efficient mass loss, and dust production can dramatically affect the chemical enrichment histories and the spectral energy distributions of their host galaxies. The ability to accurate…
Constraints on Non-flat Cosmologies with Massive Neutrinos after Planck 2015
Ratra, Bharat; Chen, Yun; Biesiada, Marek +2 more
We investigate two dark energy cosmological models (I.e., the ΛCDM and ϕCDM models) with massive neutrinos assuming two different neutrino mass hierarchies in both the spatially flat and non-flat scenarios, where in the ϕCDM model the scalar field possesses an inverse power-law potential, V(ϕ) ∝ ϕ -α (α > 0). Cosmic microwave backgr…
Space Telescope and Optical Reverberation Mapping Project. IV. Anomalous Behavior of the Broad Ultraviolet Emission Lines in NGC 5548
Im, M.; Geier, S.; Brandt, W. N. +98 more
During an intensive Hubble Space Telescope (HST) Cosmic Origins Spectrograph (COS) UV monitoring campaign of the Seyfert 1 galaxy NGC 5548 performed from 2014 February to July, the normally highly correlated far UV continuum and broad emission line variations decorrelated for ∼60-70 days, starting ∼75 days after the first HST/COS observation. Foll…
Low-metallicity Absorbers Account for Half of the Dense Circumgalactic Gas at z ≲ 1
Prochaska, J. Xavier; Lehner, Nicolas; Howk, J. Christopher +2 more
We present an analysis of the metallicity distribution of the dense circumgalactic medium (CGM) of galaxies at 0.1 ≲ z ≲ 1.1 as probed by partial Lyman limit systems (pLLSs, 16.1 < log {N}{{H}{{I}}} < 17.2) and LLSs (17.2 ≤ log {N}{{H}{{I}}} < 17.7 in our sample). The new H I-selected sample, drawn from our Hubble Sp…
The BOSS Emission-line Lens Survey. III. Strong Lensing of Lyα Emitters by Individual Galaxies
Brownstein, Joel R.; Marques-Chaves, Rui; Oguri, Masamune +8 more
We introduce the Baryon Oscillation Spectroscopic Survey (BOSS) Emission-Line Lens Survey GALaxy-Lyα EmitteR sYstems (BELLS GALLERY) Survey, which is a Hubble Space Telescope program to image a sample of galaxy-scale strong gravitational lens candidate systems with high-redshift Lyα emitters (LAEs) as the background sources. The goal of the BELLS …
First Observational Support for Overlapping Reionized Bubbles Generated by a Galaxy Overdensity
Maiolino, R.; Dickinson, M.; Giavalisco, M. +21 more
We present an analysis of deep Hubble Space Telescope (HST) multi-band imaging of the BDF field specifically designed to identify faint companions around two of the few Lyα emitting galaxies spectroscopically confirmed at z ∼ 7. Although separated by only 4.4 proper Mpc these galaxies cannot generate H II regions large enough to explain the visibi…