Search Publications
The little dippers: transits of star-grazing exocomets?
Hirano, T.; Vanderburg, A.; Ansdell, M. +9 more
We describe EPIC 205718330 and EPIC 235240266, two systems identified in the K2 data whose light curves contain episodic drops in brightness with shapes and durations similar to those of the young `dipper' stars, yet shallower by ∼1-2 orders of magnitude. These `little dippers' have diverse profile shapes with durations of ≃0.5-1.0 d and depths of…
A flat trend of star formation rate with X-ray luminosity of galaxies hosting AGN in the SCUBA-2 Cosmology Legacy Survey
Geach, James E.; Martin, Garreth; Stevens, Jason +1 more
Feedback processes from active galactic nuclei (AGN) are thought to play a crucial role in regulating star formation in massive galaxies. Previous studies using Herschel have resulted in conflicting conclusions as to whether star formation is quenched, enhanced, or not affected by AGN feedback. We use new deep 850 µm observations from the SC…
A merger shock in Abell 1367
Jones, Christine; Rudnick, Lawrence; Fossati, Matteo +10 more
Multiwavelength observations show that Abell 1367 (A1367) is a dynamically young cluster, with at least two subclusters merging along the SE-NW direction. With the wide-field XMM-Newton mosaic of A1367, we discover a previously unknown merger shock at the NW edge of the cluster. We estimate the shock Mach number from the density and temperature ju…
Storms or systematics? The changing secondary eclipse depth of WASP-12b
de Mooij, Ernst J. W.; Gibson, Neale P.; Watson, Christopher A. +4 more
WASP-12b is one of the most well-studied transiting exoplanets, as its highly inflated radius and its 1.1 d orbit around a G0-type star make it an excellent target for atmospheric categorization through observation during its secondary eclipse. We present two new secondary eclipse observations of WASP-12b, acquired an year apart with the Wide Fiel…
The second-degree gravity coefficients of Phobos from two Mars Express flybys
Pätzold, M.; Hahn, M.; Andert, T. +6 more
Several close spacecraft flybys of Phobos have been performed over the past 40 yr in order to determine the gravity field of this tiny Martian moon. In this work, the second-degree coefficients of the gravity field of Phobos were derived from the radio tracking data of two combined Mars Express flybys (2010 and 2013), by applying a least squares r…
On the emergence of THOUSANDS of absorption lines in the quasar PG 1411+442: a clumpy high-column density outflow from the broad emission-line region?
Tripp, Todd M.; Hamann, Fred; Veilleux, Sylvain +1 more
Quasar outflows are fundamental components of quasar environments that might play an important role in feedback to galaxy evolution. We report on the emergence of a remarkable new outflow absorption-line system in the quasar PG1411+442 (redshift ∼0.089) detected in the UV and visible with the Hubble Space Telescope Cosmic Origins Spectrograph and …
Discovery of the first resolved triple white dwarf
Hermes, J. J.; Gänsicke, B. T.; Tremblay, P. -E. +4 more
We report the discovery of J1953-1019, the first resolved triple white dwarf system. The triplet consists of an inner white dwarf binary and a wider companion. Using Gaia DR2 photometry and astrometry combined with our follow-up spectroscopy, we derive effective temperatures, surface gravities, masses, and cooling ages of the three components. All…
A new line on the wide binary test of gravity
Banik, Indranil
The relative velocity distribution of wide binary (WB) stars is sensitive to the law of gravity at the low accelerations typical of galactic outskirts. I consider the feasibility of this wide binary test using the `line velocity' method. This involves considering only the velocity components along the direction within the sky plane orthogonal to t…
Ultraluminous X-ray sources with flat-topped noise and QPO
Fabrika, Sergei; Atapin, Kirill; Caballero-García, Maria D.
We analysed the X-ray power density spectra of five ultraluminous X-ray sources (ULXs) NGC 5408 X-1, NGC 6946 X-1, M 82 X-1, NGC 1313 X-1, and IC 342 X-1 that are the only ULXs that display both flat-topped noise (FTN) and quasi-periodic oscillations (QPOs). We studied the QPO frequencies, fractional root-mean-square (rms) variability, X-ray lumin…
Particle acceleration in the Herbig-Haro objects HH 80 and HH 81
Carrasco-González, Carlos; Vig, Sarita; González-Martín, Omaira +4 more
We present an analysis of radio (Karl G. Jansky Very Large Array (VLA)), optical (Hubble Space Telescope (HST)), and X-ray (Chandra and XMM-Newton) observations and archival data of the Herbig-Haro objects HH 80 and HH 81 in the context of jet-cloud interactions. Our radio images are the highest angular resolution to date of these objects, allowin…