Search Publications
Cloud Structure of the Nearest Brown Dwarfs: Spectroscopic Variability of Luhman 16AB from the Hubble Space Telescope
Apai, Dániel; Marley, Mark S.; Bedin, Luigi R. +5 more
The binary brown dwarf WISE J104915.57-531906.1 (also Luhman 16AB), composed of a late-L and early-T dwarf, is a prototypical L/T transition flux reversal binary located at a distance of only 2 pc. Luhman 16B is a known variable whose light curves evolve rapidly. We present a spatially resolved spectroscopic time-series of Luhman 16A and B coverin…
Interstellar Detection of Methyl Isocyanate CH3NCO in Sgr B2(N): A Link from Molecular Clouds to Comets
Ziurys, L. M.; Halfen, D. T.; Ilyushin, V. V.
A new interstellar molecule, CH3NCO (methyl isocyanate), has been detected using the 12 m telescope of the Arizona Radio Observatory (ARO). CH3NCO was identified in spectra covering 48 GHz (68-116 GHz) in the 3 mm segment of a broadband survey of Sgr B2(N). Thirty very favorable rotational lines (Ka = 0 and Ka…
Determining the Covering Factor of Compton-thick Active Galactic Nuclei with NuSTAR
Harrison, F. A.; Stern, D.; Zhang, W. W. +19 more
The covering factor of Compton-thick (CT) obscuring material associated with the torus in active galactic nuclei (AGNs) is at present best understood through the fraction of sources exhibiting CT absorption along the line of sight (NH > 1.5 × 1024 cm-2) in the X-ray band, which reveals the average covering facto…
The Star Formation History of BCGs to z = 1.8 from the SpARCS/SWIRE Survey: Evidence for Significant In Situ Star Formation at High Redshift
Muzzin, Adam; Yee, H. K. C.; Hezaveh, Yashar +8 more
We present the results of an MIPS-24 µm study of the brightest cluster galaxies (BCGs) of 535 high-redshift galaxy clusters. The clusters are drawn from the Spitzer Adaptation of the Red-Sequence Cluster Survey, which effectively provides a sample selected on total stellar mass, over 0.2 < z < 1.8 within the Spitzer Wide-Area Infrared …
What Do IRIS Observations of Mg II k Tell Us about the Solar Plage Chromosphere?
De Pontieu, Bart; Carlsson, Mats; Leenaarts, Jorrit
We analyze observations from the Interface Region Imaging Spectrograph of the Mg ii k line, the Mg ii UV subordinate lines, and the O i 135.6 {nm} line to better understand the solar plage chromosphere. We also make comparisons with observations from the Swedish 1-m Solar Telescope of the Hα line, the Ca ii 8542 line, and Solar Dynamics Observator…
An Increasing Stellar Baryon Fraction in Bright Galaxies at High Redshift
Papovich, Casey; Finkelstein, Steven L.; Ferguson, Henry C. +12 more
Recent observations have shown that the characteristic luminosity of the rest-frame ultraviolet (UV) luminosity function does not significantly evolve at 4 < z < 7 and is approximately {M}{UV}*∼ -21. We investigate this apparent non-evolution by examining a sample of 173 bright, MUV < -21 galaxies at z = 4…
The Broadband XMM-Newton and NuSTAR X-Ray Spectra of Two Ultraluminous X-Ray Sources in the Galaxy IC 342
Hailey, Charles J.; Fabian, Andrew C.; Walton, Dominic J. +15 more
We present results for two ultraluminous X-ray sources (ULXs), IC 342 X-1 and IC 342 X-2, using two epochs of XMM-Newton and NuSTAR observations separated by ~7 days. We observe little spectral or flux variability above 1 keV between epochs, with unabsorbed 0.3-30 keV luminosities being 1.04+0.08-0.06 × 1040 erg s<…
Light Bridge in a Developing Active Region. I. Observation of Light Bridge and its Dynamic Activity Phenomena
Toriumi, Shin; Cheung, Mark C. M.; Katsukawa, Yukio
Light bridges, the bright structures that divide the umbra of sunspots and pores into smaller pieces, are known to produce a wide variety of activity events in solar active regions (ARs). It is also known that the light bridges appear in the assembling process of nascent sunspots. The ultimate goal of this series of papers is to reveal the nature …
Deep Chandra, HST-COS, and Megacam Observations of the Phoenix Cluster: Extreme Star Formation and AGN Feedback on Hundred Kiloparsec Scales
McNamara, Brian R.; Miller, Eric D.; Fabian, Andrew C. +17 more
We present new ultraviolet, optical, and X-ray data on the Phoenix galaxy cluster (SPT-CLJ2344-4243). Deep optical imaging reveals previously undetected filaments of star formation, extending to radii of ∼50-100 kpc in multiple directions. Combined UV-optical spectroscopy of the central galaxy reveals a massive (2 × 109 M⊙), …
X-Ray High-resolution Spectroscopy Reveals Feedback in a Seyfert Galaxy from an Ultra-fast Wind with Complex Ionization and Velocity Structure
Costantini, E.; Guainazzi, M.; Giroletti, M. +5 more
Winds outflowing from active galactic nuclei (AGNs) may carry significant amounts of mass and energy out to their host galaxies. In this paper we report the detection of a sub-relativistic outflow observed in the narrow line Seyfert 1 galaxy IRAS 17020+4544 as a series of absorption lines corresponding to at least five absorption components with a…