Search Publications
A Cool Core Disturbed: Observational Evidence for the Coexistence of Subsonic Sloshing Gas and Stripped Shock-heated Gas around the Core of RX J1347.5-1145
Kohno, Kotaro; Oguri, Masamune; Iono, Daisuke +13 more
RX J1347.5-1145 (z = 0.451) is one of the most luminous X-ray galaxy clusters; it hosts a prominent cool core and exhibits a signature of a major merger. We present the first direct observational evidence for the subsonic nature of the sloshing motion of the cool core. We find that a residual X-ray image from the Chandra X-ray Observatory after re…
Propagating Spectropolarimetric Disturbances in a Large Sunspot
Erdélyi, R.; Ermolli, I.; Murabito, M. +7 more
We present results derived from the analysis of spectropolarimetric measurements of active region AR12546, which represents one of the largest sunspots to have emerged onto the solar surface over the last 20 years. The region was observed with full-Stokes scans of the Fe I 617.3 nm and Ca II 854.2 nm lines with the Interferometric BIdimensional Sp…
Stellar and Planetary Characterization of the Ross 128 Exoplanetary System from APOGEE Spectra
Cunha, Katia; Smith, Verne V.; Souto, Diogo +14 more
The first detailed chemical abundance analysis of the M-dwarf (M4.0) exoplanet-hosting star Ross 128 is presented here, based upon near-infrared (1.5-1.7 µm), high-resolution (R ∼ 22,500) spectra from the SDSS Apache Point Galactic Evolution Experiment survey. We determined precise atmospheric parameters T eff = 3231 ± 100 K, log …
Discovery of an Ultraviolet Counterpart to an Ultrafast X-Ray Outflow in the Quasar PG 1211+143
Kriss, Gerard A.; Lee, Julia C.; Danehkar, Ashkbiz +5 more
We observed the quasar PG 1211+143 using the Cosmic Origins Spectrograph on the Hubble Space Telescope in 2015 April as part of a joint campaign with the Chandra X-ray Observatory and the Jansky Very Large Array. Our ultraviolet spectra cover the wavelength range 912-2100 Å. We find a broad absorption feature (∼ 1080 {km} {{{s}}}-1) at …
Spectral and Imaging Observations of a Current Sheet Region in a Small-scale Magnetic Reconnection Event
Xue, Zhike; Yan, Xiaoli; Wang, Jincheng +5 more
We report a possible current sheet region associated with a small-scale magnetic reconnection event by using the spectral and imaging observations of the Interface Region Imaging Spectrograph (IRIS) and the magnetograms obtained by the Solar Dynamics Observatory on 2016 August 08. The length and width of the current sheet region are estimated to b…
Super-Eddington Accretion in the WISE-selected Extremely Luminous Infrared Galaxy W2246-0526
Tsai, Chao-Wei; Wright, Edward L.; Jun, Hyunsung D. +8 more
We use optical and near-infrared spectroscopy to observe rest-UV emission lines and estimate the black hole mass of WISEA J224607.56-052634.9 (W2246-0526) at z = 4.601, the most luminous hot, dust-obscured galaxy yet discovered by WISE. From the broad component of the Mg II 2799 Å emission line, we measure a black hole mass of log(M BH/…
An ALMA Survey of Faint Disks in the Chamaeleon I Star-forming Region: Why Are Some Class II Disks so Faint?
Pascucci, Ilaria; Herczeg, Gregory J.; Henning, Thomas +6 more
ALMA surveys of nearby star-forming regions have shown that the dust mass in the disk is correlated with the stellar mass, but with a large scatter. This scatter could indicate either different evolutionary paths of disks or different initial conditions within a single cluster. We present ALMA Cycle 3 follow-up observations for 14 Class II disks t…
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…
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]…
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…