Search Publications
Discovery of Three Distant, Cold Brown Dwarfs in the WFC3 Infrared Spectroscopic Parallels Survey
Scarlata, C.; Malkan, M.; Teplitz, H. +12 more
We present the discovery of three late-type (>=T4.5) brown dwarfs, including a probable Y dwarf, in the WFC3 Infrared Spectroscopic Parallels (WISP) survey. We use the G141 grism spectra to determine the spectral types of the dwarfs and derive distance estimates based on a comparison with nearby T dwarfs with known parallaxes. These are the mos…
SN 2002bu—Another SN 2008S-like Transient
Kochanek, C. S.; Dai, X.; Szczygieł, D. M.
We observed supernova (SN) 2002bu in the near-IR with the Hubble Space Telescope (HST), the mid-IR with the Spitzer Space Telescope, and in X-rays with Swift 10 years after the explosion. If the faint L H ~ 102 L ⊙ HST near-IR source at the transient position is the near-IR counterpart of SN 2002bu, then the source…
A Period Distribution of X-Ray Binaries Observed in the Central Region of M31 with Chandra and the Hubble Space Telescope
Zezas, A.; Murray, S. S.; Garcia, M. R. +4 more
Almost all Galactic black hole (BH) binaries with low-mass donor stars are transient X-ray sources; we expect most of the X-ray transients observed in external galaxies to be BH binaries also. Obtaining period estimates for extragalactic transients is challenging, but the resulting period distribution is an important tool for modeling the evolutio…
Observational Constraints on the Molecular Gas Content in Nearby Starburst Dwarf Galaxies
McQuinn, Kristen B. W.; Cannon, John M.; Dolphin, Andrew E. +5 more
Using star formation histories derived from optically resolved stellar populations in 19 nearby starburst dwarf galaxies observed with the Hubble Space Telescope, we measure the stellar mass surface densities of stars newly formed in the bursts. By assuming a star formation efficiency (SFE), we then calculate the inferred gas surface densities pre…
Solar Energetic Particle Events and the Kiplinger Effect
Kahler, S. W.
The Kiplinger effect is an observed association of solar energetic (E > 10 MeV) particle (SEP) events with a "soft-hard-harder" (SHH) spectral evolution during the extended phases of the associated solar hard (E > 30 keV) X-ray (HXR) flares. Besides its possible use as a space weather predictor of SEP events, the Kiplinger effect has been in…
Is FS Tau B Driving an Asymmetric Jet?
Ohashi, Nagayoshi; Pyo, Tae-Soo; Liu, Chun-Fan +6 more
FS Tau B is one of the few T Tauri stars that possess a jet and a counterjet as well as an optically visible cavity wall. We obtained images and spectra of its jet-cavity system in the near-infrared H and K bands using the Subaru/Infrared Camera and Spectrograph and detected the jet and the counterjet in the [Fe II] 1.644 µm line for the fir…
Inverse Compton X-Ray Halos around High-z Radio Galaxies: A Feedback Mechanism Powered by Far-infrared Starbursts or the Cosmic Microwave Background?
Lehmer, B. D.; Smail, Ian; Alexander, D. M. +1 more
We report the detection of extended X-ray emission around two powerful radio galaxies at z ~ 3.6 (4C 03.24 and 4C 19.71) and use these to investigate the origin of extended, inverse Compton (IC) powered X-ray halos at high redshifts. The halos have X-ray luminosities of L X ~ 3 × 1044 erg s-1 and sizes of ~60 kpc. …
The ChaMPlane Bright X-Ray Sources—Galactic Longitudes l = 2°-358°
Penner, Kyle; Laycock, Silas; van den Berg, Maureen +4 more
The Chandra Multi-wavelength Plane (ChaMPlane) survey aims to constrain the Galactic population of mainly accretion-powered, but also coronal, low-luminosity X-ray sources (L X <~ 1033 erg s-1). To investigate the X-ray source content in the plane at fluxes F X >~ 3 × 10-14 erg s-1<…
DASCH Discovery of a Possible Nova-like Outburst in a Peculiar Symbiotic Binary
Quinn, Samuel N.; Orosz, Jerome A.; Grindlay, Jonathan E. +4 more
We present photometric and spectroscopic observations of a peculiar variable (designated DASCH J075731.1+201735 or J0757) discovered from our DASCH project using the digitized Harvard College Observatory archival photographic plates. It brightened by about 1.5 mag in B within a year starting in 1942, and then slowly faded back to its pre-outburst …
The Spindle: An Irradiated Disk and Bent Protostellar Jet in Orion
Ginsburg, Adam; Youngblood, Allison; Bally, John
We present Hubble Space Telescope observations of a bent, pulsed Herbig-Haro jet, HH 1064, emerging from the young star Parenago 2042 embedded in the H II region NGC 1977 located about 30' north of the Orion Nebula. This outflow contains eight bow shocks in the redshifted western lobe and five bow shocks in the blueshifted eastern lobe. Shocks wit…