Search Publications
A Spectroscopic Census in Young Stellar Regions: The σ Orionis Cluster
Briceño, Cesar; Hartmann, Lee; Calvet, Nuria +7 more
We present a spectroscopic survey of the stellar population of the σ Orionis cluster. We have obtained spectral types for 340 stars. Spectroscopic data for spectral typing come from several spectrographs with similar spectroscopic coverage and resolution. More than half of the stars in our sample are members confirmed by the presence of lithium in…
Radio Timing and Optical Photometry of the Black Widow System PSR J1518+0204C in the Globular Cluster M5
Dalessandro, E.; Ransom, S. M.; Ferraro, F. R. +5 more
We report on the determination of astrometric, spin, and orbital parameters for PSR J1518+0204C, a "black widow" binary millisecond pulsar in the globular cluster (GC) M5. The accurate position and orbital parameters obtained from radio timing allowed us to search for the optical companion. By using WFC3/Hubble Space Telescope images, we identifie…
Herschel Far-infrared Photometry of the Swift Burst Alert Telescope Active Galactic Nuclei Sample of the Local Universe. I. PACS Observations
Barger, A. J.; Cowie, L. L.; Mushotzky, R. F. +2 more
Far-Infrared (FIR) photometry from the Photodetector Array Camera and Spectrometer on the Herschel Space Observatory is presented for 313 nearby, hard X-ray selected galaxies from the 58 month Swift Burst Alert Telescope (BAT) Active Galactic Nuclei catalog. The present data do not distinguish between the FIR luminosity distributions at 70 and 160…
The 2011 Outburst of Recurrent Nova T Pyx: X-ray Observations Expose the White Dwarf Mass and Ejection Dynamics
Sokoloski, J. L.; Chomiuk, Laura; Kuulkers, Erik +9 more
The recurrent nova T Pyx underwent its sixth historical outburst in 2011, and became the subject of an intensive multi-wavelength observational campaign. We analyze data from the Swift and Suzaku satellites to produce a detailed X-ray light curve augmented by epochs of spectral information. X-ray observations yield mostly non-detections in the fir…
A Tidal Disruption Event in a nearby Galaxy Hosting an Intermediate Mass Black Hole
Troja, E.; Butler, N. R.; Cenko, S. B. +9 more
We report the serendipitous discovery of a bright point source flare in the Abell cluster A1795 with archival EUVE and Chandra observations. Assuming the EUVE emission is associated with the Chandra source, the X-ray 0.5-7 keV flux declined by a factor of ~2300 over a time span of 6 yr, following a power-law decay with index ~2.44 ± 0.40. The Chan…
The Nature of Hα-selected Galaxies at z > 2. II. Clumpy Galaxies and Compact Star-forming Galaxies
Koyama, Yusei; Kodama, Tadayuki; Hayashi, Masao +3 more
We present the morphological properties of Hα-selected galaxies at z > 2 in SXDF-UDS-CANDELS field. With high-resolution optical/near-infrared images obtained by the Hubble Space Telescope, we identify giant clumps within the Hα emitters (HAEs). We find that at least 41% of our sample shows clumpy structures in the underlying disks. The color g…
Evidence for Wave Heating of the Quiet-Sun Corona
Hahn, M.; Savin, D. W.
We have measured the energy and dissipation of Alfvénic waves in the quiet Sun. A magnetic field model was used to infer the location and orientation of the magnetic field lines along which the waves are expected to travel. The waves were measured using spectral lines to infer the wave amplitude. The waves cause a non-thermal broadening of the spe…
The Dwarfs beyond: The Stellar-to-halo Mass Relation for a New Sample of Intermediate Redshift Low-mass Galaxies
Ellis, Richard S.; Newman, Andrew B.; Miller, Sarah H. +1 more
A number of recent challenges to the standard ΛCDM paradigm relate to discrepancies that arise in comparing the abundance and kinematics of local dwarf galaxies with the predictions of numerical simulations. Such arguments rely heavily on the assumption that the Local Volume's dwarf and satellite galaxies form a representative distribution in term…
Ultraviolet Observations of Super-Chandrasekhar Mass Type Ia Supernova Candidates with Swift UVOT
Wang, Lifan; Krisciunas, Kevin; Milne, Peter +6 more
Among Type Ia supernovae (SNe Ia), a class of overluminous objects exist whose ejecta mass is inferred to be larger than the canonical Chandrasekhar mass. We present and discuss the UV/optical photometric light curves, colors, absolute magnitudes, and spectra of three candidate Super-Chandrasekhar mass SNe—2009dc, 2011aa, and 2012dn—observed with …
Measurements of EUV Coronal Holes and Open Magnetic Flux
Liu, Y.; Qiu, J.; Lowder, C. +1 more
Coronal holes are regions on the Sun's surface that map the footprints of open magnetic field lines. We have developed an automated routine to detect and track boundaries of long-lived coronal holes using full-disk extreme-ultraviolet (EUV) images obtained by SOHO/EIT, SDO/AIA, and STEREO/EUVI. We measure coronal hole areas and magnetic flux in th…