Search Publications
Quasars Have Fewer Close Companions than Normal Galaxies
Fan, Xiaohui; McGreer, Ian D.; Huang, Yun-Hsin +2 more
We investigate the distribution of companion galaxies around quasars using Hubble Space Telescope (HST) Advanced Camera for Surveys Wide Field Camera (ACS/WFC) archival images. Our master sample contains 532 quasars that have been observed by HST ACS/WFC, spanning a wide range of luminosity (-31 < M i (z = 2) < -23) and redshift …
Spectrophotometric Redshifts for z ∼ 1 Galaxies and Predictions for Number Densities with WFIRST and Euclid
Hathi, Nimish P.; Cohen, Seth; Windhorst, Rogier A. +3 more
We investigate the accuracy of 4000 Å/Balmer-break based redshifts by combining Hubble Space Telescope (HST) grism data with photometry. The grism spectra are from the Probing Evolution And Reionization Spectroscopically survey with HST using the G800L grism on the Advanced Camera for Surveys. The photometric data come from a compilation by the 3D…
Infrared Galaxies in the Field of the Massive Cluster Abell S1063: Discovery of a Luminous Kiloparsec-sized H II Region in a Gravitationally Lensed Infrared-luminous Galaxy at z = 0.6
Richard, Johan; Weiner, Benjamin; Egami, Eiichi +10 more
Using the Spitzer Space Telescope and Herschel Space Observatory, we have conducted a survey of IR galaxies in the field of the galaxy cluster AS1063 at z = 0.347, which is one of the most massive clusters known and a target of the Hubble Space Telescope (HST) Cluster Lensing and Supernova Survey with Hubble and the Frontier Field surveys. The Spi…
The Nature of Class I Sources: Periodic Variables in Orion
Duchene, Gaspard; Ellithorpe, Elizabeth A.; Stahler, Steven W.
We present a quantitative, empirically based argument that at least some Class I sources are low-mass, pre-main-sequence stars surrounded by spatially extended envelopes of dusty gas. The source luminosity arises principally from stellar gravitational contraction, as in optically visible pre-main-sequence stars that lack such envelopes. We base ou…
Hunting Young White Dwarfs at the Center of Planetary Nebulae
Weidmann, Walter A.; Ahumada, Javier A.; Miller Bertolami, Marcelo M. +1 more
We present Gemini-South observations of nine faint and extended planetary nebulae (PNe). Using direct images taken with the spectrograph Gemini-South multi-object spectrograph (GMOS), we built the (u\prime -g\prime ) versus (g\prime -r\prime ) diagrams of the stars in the observed areas which allowed us …
Integrated Spectra of Milky Way Globular Clusters
Trevisan, M.; Barbuy, B.; Moura, T. C. +1 more
Integrated spectra of Milky Way globular clusters (GCs) are reproduced by computing synthetic spectra taking into account individual element abundances. Five clusters were selected from their location in the Galactic bulge, for which integrated spectra were available in the WiFeS Atlas of Galactic Globular Cluster Spectra project. Our aim is to fu…
Relativistic Astronomy. II. In-flight Solution of Motion and Test of Special Relativity Light Aberration
Zhang, Bing; Yang, Yuan-Pei; Zhu, Jin-Ping
The Breakthrough Starshot project aims to send centimeter-sized, gram-scale “StarChip” probes to Alpha Centauri at a speed of ∼0.2 c. On the other hand, Zhang & Li recently proposed that transrelativistic cameras may be sent to any direction to study astronomical objects and test special relativity. To conduct such “relativistic astronomy,” on…
An ALMA/HST Study of Millimeter Dust Emission and Star Clusters
Dale, D. A.; Calzetti, D.; Smith, L. J. +7 more
We present results from a joint ALMA/HST study of the nearby spiral galaxy NGC 628. We combine the Hubble Space Telescope (HST) Legacy ExtraGalactic UV Survey (LEGUS) database of over 1000 stellar clusters in NGC 628 with ALMA Cycle 4 mm/submillimeter observations of the cold dust continuum that span ∼15 kpc2 including the nuclear regio…
Hubble Space Telescope Far-UV Spectroscopy of the Short Orbital Period Recurrent Nova CI Aql: Implications for White Dwarf Mass Evolution
Williams, Robert E.; Wilson, R. E.; Sion, Edward M. +3 more
An Hubble Space Telescope Cosmic Object Spectrograph Far UV spectrum (1170 Å to 1800 Å) was obtained for the short orbital period recurrent novae (T Pyxidis subclass), CI Aquilae. CI Aql is the only classical Cataclysmic variable (CV) known to have two eclipses of a sensible depth per orbit cycle and also to have pre- and post-outburst light curve…
Discovery and Identification of MAXI J1621-501 as a Type I X-Ray Burster with a Super-orbital Period
Göğüş, Ersin; Bahramian, Arash; Chakrabarty, Deepto +26 more
MAXI J1621-501 is the first Swift/XRT Deep Galactic Plane Survey transient that was followed up with a multitude of space missions (NuSTAR, Swift, Chandra, NICER, INTEGRAL, and MAXI) and ground-based observatories (Gemini, IRSF, and ATCA). The source was discovered with MAXI on 2017 October 19 as a new, unidentified transient. Further observations…