Search Publications
Simultaneous Constraints on the Mass and Radius of Aql X-1 from Quiescence and X-Ray Burst Observations
Chen, Li; Falanga, Maurizio; Li, Zhaosheng +2 more
The measurement of neutron star mass and radius is one of the most direct ways to distinguish between various dense matter equations of state. The mass and radius of accreting neutron stars hosted in low-mass X-ray binaries can be constrained by several methods, including photospheric radius expansion from type I X-ray bursts and from quiescent sp…
Signatures of Hot Molecular Hydrogen Absorption from Protoplanetary Disks. I. Non-thermal Populations
Loyd, R. O. Parke; Kruczek, Nicholas; France, Kevin +2 more
The environment around protoplanetary disks (PPDs) regulates processes that drive the chemical and structural evolution of circumstellar material. We perform a detailed empirical survey of warm molecular hydrogen (H2) absorption observed against H I-Lyα (Lyα: λ1215.67) emission profiles for 22 PPDs, using archival Hubble Space Telescope…
The Carnegie-Chicago Hubble Program: Discovery of the Most Distant Ultra-faint Dwarf Galaxy in the Local Universe
Lee, Myung Gyoon; Jang, In Sung; Seibert, Mark +3 more
Ultra-faint dwarf galaxies (UFDs) are the faintest known galaxies, and due to their incredibly low surface brightness, it is difficult to find them beyond the Local Group. We report a serendipitous discovery of a UFD, Fornax UFD1, in the outskirts of NGC 1316, a giant galaxy in the Fornax cluster. The new galaxy is located at a projected radius of…
HST Detection of Extended Neutral Hydrogen in a Massive Elliptical at z = 0.4
Zahedy, Fakhri S.; Chen, Hsiao-Wen; Rauch, Michael +1 more
We report the first detection of extended neutral hydrogen (H I) gas in the interstellar medium (ISM) of a massive elliptical galaxy beyond z∼ 0. The observations utilize the doubly lensed images of QSO HE 0047-1756 at {z}{QSO}=1.676 as absorption-line probes of the ISM in the massive ({M}{star}≈ {10}11 {M}⊙ <…
The Nuclear X-Ray Emission-line Structure in NGC 2992 Revealed by Chandra-HETGS
Nowak, M. A.; Marshall, H. L.; Murphy, K. D.
We present the narrow emission-line structure revealed by a 135 ks Chandra observation of Seyfert galaxy NGC 2992, using the High Energy Transmission Grating Spectrometer. The source was observed in an historically low-flux state. Using a Bayesian Block search technique, we detected neutral Si Kα and S Kα fluorescence and two additional lines that…
Herschel Extreme Lensing Line Observations: [CII] Variations in Galaxies at Redshifts z=1-3
Carilli, Chris; Papovich, Casey; Strauss, Michael A. +14 more
We observed the [C II] line in 15 lensed galaxies at redshifts 1 < z < 3 using HIFI on the Herschel Space Observatory and detected 14/15 galaxies at 3σ or better. High magnifications enable even modestly luminous galaxies to be detected in [C II] with Herschel. The [C II] luminosity in this sample ranges from 8 × 107 L⊙…
Structure and Dynamics of Cool Flare Loops Observed by the Interface Region Imaging Spectrograph
Heinzel, P.; Berlicki, A.; Liu, W. +1 more
Flare loops were well observed with the Interface Region Imaging Spectrograph (IRIS) during the gradual phase of two solar flares on 2014 March 29 and 2015 June 22. Cool flare loops are visible in various spectral lines formed at chromospheric and transition-region temperatures and exhibit large downflows which correspond to the standard scenario.…
The Stochastic X-Ray Variability of the Accreting Millisecond Pulsar MAXI J0911-655
Bult, Peter
In this work, I report on the stochastic X-ray variability of the 340 Hz accreting millisecond pulsar MAXI J0911-655. Analyzing pointed observations of the XMM-Newton and NuSTAR observatories, I find that the source shows broad band-limited stochastic variability in the 0.01{--}10 {Hz} range with a total fractional variability of ∼ 24 % rms in the…
Near-infrared Spectroscopy of Five Ultra-massive Galaxies at 1.7 < z < 2.7
Muzzin, Adam; Labbé, Ivo; Quadri, Ryan +13 more
We present the results of a pilot near-infrared spectroscopic campaign of five very massive galaxies ({log}({M}\star /{M}⊙ )> 11.45) in the range of 1.7< z< 2.7. We measure an absorption feature redshift for one galaxy at {z}{spec}=2.000+/- 0.006. For the remaining galaxies, we combine the photometry with …
Propagation and Interaction Properties of Successive Coronal Mass Ejections in Relation to a Complex Type II Radio Burst
Liu, Ying D.; Zhao, Xiaowei; Zhu, Bei
We examine the propagation and interaction properties of three successive coronal mass ejections (CMEs) from 2001 November 21-22, with a focus on their connection with the behaviors of the associated long-duration complex type II radio burst. In combination with coronagraph and multi-point in situ observations, the long-duration type II burst prov…