Search Publications
Possible Signatures of a Termination Shock in the 2014 March 29 X-class Flare Observed by IRIS
Reeves, Katharine K.; Polito, Vanessa; Galan, Giselle +1 more
The standard model of flares predicts the existence of a fast-mode magnetohydrodynamic shock above the looptops, also known as termination shock (TS), as the result of the downward-directed outflow reconnection jets colliding with the closed magnetic loops. A crucial spectral signature of a TS is the presence of large Doppler shifts in the spectra…
Generation of a circumstellar gas disc by hot Jupiter WASP-12b
Frank, Adam; Dobbs-Dixon, Ian; Fossati, Luca +3 more
Observations of transiting extra-solar planets provide rich sources of data for probing the in-system environment. In the WASP-12 system, a broad depression in the usually bright Mg II h&k lines has been observed, in addition to atmospheric escape from the extremely hot Jupiter WASP-12b. It has been hypothesized that a translucent circumstella…
Formation time-scales for high-mass X-ray binaries in M33
Dolphin, Andrew E.; Williams, Benjamin F.; Gilbert, Karoline M. +4 more
We have identified 55 candidate high-mass X-ray binaries (HMXBs) in M33 using available archival Hubble Space Telescope (HST) and Chandra imaging to find blue stars associated with X-ray positions. We use the HST photometric data to model the colour-magnitude diagrams in the vicinity of each candidate HMXB to measure a resolved recent star formati…
Coma morphology of comet 67P controlled by insolation over irregular nucleus
Jorda, L.; Lamy, P. L.; Lara, L. M. +42 more
While the structural complexity of cometary comae is already recognizable from telescopic observations1, the innermost region, within a few radii of the nucleus, was not resolved until spacecraft exploration became a reality2,3. The dust coma displays jet-like features of enhanced brightness superposed on a diffuse background…
Characterizing the circum-galactic medium of damped Lyman-α absorbing galaxies
Pieri, Matthew; York, Donald G.; Péroux, Céline +8 more
Gas flows in and out of galaxies through their circum-galactic medium (CGM) are poorly constrained and direct observations of this faint, diffuse medium remain challenging. We use a sample of five z ∼ 1-2 galaxy counterparts to damped Lyman-α absorbers (DLAs) to combine data on cold gas, metals and stellar content of the same galaxies. We present …
Recurring obscuration in NGC 3783
Kaastra, J. S.; Kriss, G. A.; Bianchi, S. +14 more
Context. Obscuration of the continuum emission from active galactic nuclei by streams of gas with relatively high velocity (>1000 km s-1) and column density (>3 × 1025 m-2) has been seen in a few Seyfert galaxies. This obscuration has a transient nature. In December 2016 we witnessed such an event in NGC 3783…
The R-Process Alliance: Chemical Abundances for a Trio of r-process-enhanced Stars—One Strong, One Moderate, and One Mild
Casey, Andrew R.; Beers, Timothy C.; Placco, Vinicius M. +9 more
We present detailed chemical abundances of three new bright (V ∼ 11), extremely metal-poor ([Fe/H] ∼ -3.0), r-process-enhanced halo red giants based on high-resolution, high-S/N Magellan/MIKE spectra. We measured abundances for 20-25 neutron-capture elements in each of our stars. J1432-4125 is among the most r-process-rich r-II stars, with [Eu/Fe]…
Multiband counterparts of two eclipsing ultraluminous X-ray sources in M 51
Motch, C.; Miller-Jones, J. C. A.; Soria, R. +5 more
We present the discovery and interpretation of ionized nebulae around two ultraluminous X-ray sources in M 51; both sources share the rare property of showing X-ray eclipses by their companion stars and are therefore prime targets for follow-up studies. Using archival Hubble Space Telescope images, we found an elongated, 100-pc-long emission-line …
The Effects of Stellar Companions on the Observed Transiting Exoplanet Radius Distribution
Howell, Steve B.; Hirsch, Lea A.; Ciardi, David R. +2 more
Understanding the distribution and occurrence rate of small planets was a fundamental goal of the Kepler transiting exoplanet mission, and could be improved with K2 and Transiting Exoplanet Survey Satellite (TESS). Deriving accurate exoplanetary radii requires accurate measurements of the host star radii and the planetary transit depths, including…
Testing Viable f(T) Models with Current Observations
Wu, Puxun; Yu, Hongwei; Xu, Bing
We perform observational tests on the f(T) gravity with the BAO data (including the BOSS DR 12 galaxy sample, the DR12 Lyα-Forests measurement, the new eBOSS DR14 quasar sample, the 6dFGS, and the SDSS), the CMB distance priors from the Planck 2015, the SNIa data from the joint light-curve analysis, the latest H(z) data, and the local value of the…