Search Publications
A Survey of Protoplanetary Disks Using the Keck/NIRC2 Vortex Coronagraph
Ren, Bin B.; Knutson, Heather A.; Uyama, Taichi +34 more
Recent Atacama Large Millimeter/submillimeter Array (ALMA) observations of protoplanetary disks in the millimeter continuum have shown a variety of radial gaps, cavities, and spiral features. These substructures may be signposts for ongoing planet formation, and therefore these systems are promising targets for direct imaging planet searches in th…
A 350 MHz Green Bank Telescope Survey of Unassociated Fermi LAT Sources: Discovery and Timing of 10 Millisecond Pulsars
Camilo, F.; Guillemot, L.; Johnson, T. J. +18 more
We have searched for radio pulsations toward 49 Fermi Large Area Telescope (LAT) 1FGL Catalog γ-ray sources using the Green Bank Telescope at 350 MHz. We detected 18 millisecond pulsars (MSPs) in blind searches of the data; 10 of these were discoveries unique to our survey. 16 are binaries, with eight having short orbital periods P B …
Isochrone fitting of the open cluster M67 in the era of Gaia and improved model physics
Stello, Dennis; Hon, Marc; Pinsonneault, Marc H. +3 more
The Gaia mission has provided highly accurate observations that have significantly reduced the scatter in the colour-magnitude diagrams of open clusters. As a result of the improved isochrone sequence of the open cluster M67, we have created new stellar models that avoid commonly used simplifications in 1D stellar modelling, such as mass-independe…
A search for high-redshift direct-collapse black hole candidates in the PEARLS north ecliptic pole field
Finkelstein, Steven L.; Grogin, Norman A.; Koekemoer, Anton M. +33 more
Direct-collapse black holes (DCBHs) of mass ∼104 − 105 M⊙ that form in HI-cooling halos in the early Universe are promising progenitors of the ≳109 M⊙ supermassive black holes that fuel observed z ≳ 7 quasars. Efficient accretion of the surrounding gas onto such DCBH seeds may render them suff…
Black Hole Mass and Eddington Ratio Distribution of Hot Dust-obscured Galaxies
Tsai, Chao-Wei; Jun, Hyunsung D.; Eisenhardt, Peter R. M. +8 more
Hot dust-obscured galaxies (Hot DOGs) are a rare population of hyperluminous infrared galaxies discovered by the Wide-field Infrared Survey Explorer mission. Despite the significant obscuration of the active galactic nucleus (AGN) by dust in these systems, pronounced broad and blueshifted emission lines are often observed. Previous work has shown …
A Buddy for Betelgeuse: Binarity as the Origin of the Long Secondary Period in α Orionis
Joyce, Meridith; Molnár, László; Goldberg, Jared A.
We predict the existence of α Ori B, a low-mass companion orbiting Betelgeuse. This is motivated by the presence of a 2170 day long secondary period (LSP) in Betelgeuse's lightcurve, a periodicity that is ≈5 times longer than the star's 416 day fundamental radial pulsation mode. While binarity is currently the leading hypothesis for LSPs in genera…
The Cause of the Difference in the Propagation Distances between Compact and Transient Jets in Black Hole X-Ray Binaries
Zdziarski, Andrzej A.; Heinz, Sebastian
Accreting black hole binaries change their properties during evolution, passing through two main luminous states, dominated by either hard or soft X-rays. In the hard state, steady compact jets emitting multiwavelength radiation are present. Those jets are usually observed in radio, and when resolved, their extent is ≲1015 cm. Then, dur…
Upstream Plasma Waves and Downstream Magnetic Reconnection at a Reforming Quasi-parallel Shock
Yang, Zhongwei; Lu, Quanming; Gao, Xinliang +4 more
With the help of a two-dimensional particle-in-cell simulation model, we investigate the long-time evolution (near $100{{\rm{\Omega }}}_{i0}^{-1}$ , where Ω i0 is the ion gyrofrequency in the upstream) of a quasi-parallel shock. Some of the upstream ions are reflected by the shock front, and their interactions with the incident ions exc…
Identifying Jittering Jet-shaped Ejecta in the Cygnus Loop Supernova Remnant
Soker, Noam; Shishkin, Dmitry; Kaye, Roy
Analyzing images of the Cygnus Loop, a core-collapse supernova (CCSN) remnant, in different emission bands, we identify a point-symmetrical morphology composed of three symmetry axes that we attribute to shaping by three pairs of jets. The main jet axis has an elongated S shape, appearing as a faint narrow zone in visible and UV. We term it the S-…
Infrared spectroscopy of SWIFT J0850.8-4219: identification of the second red supergiant X-ray binary in the Milky Way
Soria, Roberto; De, Kishalay; Daly, Fiona A.
High-mass X-ray binaries hosting red supergiant (RSG) donors are a rare but crucial phase in massive stellar evolution, with only one source previously known in the Milky Way. In this letter, we present the identification of the second Galactic RSG X-ray binary SWIFT J0850.8-4219. We identify the source 2MASS 08504008-4211514 as the likely infrare…