Search Publications
IROCKS: Spatially Resolved Kinematics of z ∼ 1 Star-forming Galaxies
Juneau, Stéphanie; Salim, Samir; Armus, Lee +4 more
We present results from the Intermediate Redshift OSIRIS Chemo-Kinematic Survey (IROCKS) for sixteen z ∼ 1 and one z ∼ 1.4 star-forming galaxies. All galaxies were observed with OSIRIS with the laser guide star adaptive optics system at Keck Observatory. We use rest-frame nebular Hα emission lines to trace morphologies and kinematics of ionized ga…
The Peculiar Debris Disk of HD 111520 as Resolved by the Gemini Planet Imager
Matthews, Brenda C.; Duchêne, Gaspard; Oppenheimer, Rebecca +33 more
Using the Gemini Planet Imager, we have resolved the circumstellar debris disk around HD 111520 at a projected range of ∼30-100 AU in both total and polarized H-band intensity. The disk is seen edge-on at a position angle of 165° along the spine of emission. A slight inclination and asymmetric warp are covariant and alter the interpretation of the…
HST-COS Observations of AGNs. III. Spectral Constraints in the Lyman Continuum from Composite COS/G140L Data
Stevans, Matthew L.; Shull, J. Michael; Danforth, Charles W. +1 more
The rest-frame ultraviolet (UV) spectra of active galactic nuclei (AGNs) are important diagnostics of both accretion disk physics and their contribution to the metagalactic ionizing UV background. Though the mean AGN spectrum is well characterized with composite spectra at wavelengths greater than 912 Å, the shorter-wavelength extreme-UV (EUV) rem…
Absolute Calibration of the Radio Astronomy Flux Density Scale at 22 to 43 GHz Using Planck
López-Caniego, M.; Partridge, B.; Rocha, G. +5 more
The Planck mission detected thousands of extragalactic radio sources at frequencies from 28 to 857 GHz. Planck's calibration is absolute (in the sense that it is based on the satellite’s annual motion around the Sun and the temperature of the cosmic microwave background), and its beams are well characterized at sub-percent levels. Thus, Planck's f…
SHIELD: Neutral Gas Kinematics and Dynamics
McQuinn, Kristen B. W.; Cannon, John M.; Skillman, Evan D. +22 more
We present kinematic analyses of the 12 galaxies in the “Survey of H I in Extremely Low-mass Dwarfs” (SHIELD). We use multi-configuration interferometric observations of the H I 21 cm emission line from the Karl G. Jansky Very Large Array (VLA)22 to produce image cubes at a variety of spatial and spectral resolutions. Both two- and thre…
Two Distinct-absorption X-Ray Components from Type IIn Supernovae: Evidence for Asphericity in the Circumstellar Medium
Sugawara, Yasuharu; Katsuda, Satoru; Kawabata, Koji +7 more
We present multi-epoch X-ray spectral observations of three Type IIn supernovae (SNe), SN 2005kd, SN 2006jd, and SN 2010jl, acquired with Chandra, XMM-Newton, Suzaku, and Swift. Previous extensive X-ray studies of SN 2010jl have revealed that X-ray spectra are dominated by thermal emission, which likely arises from a hot plasma heated by a forward…
Star Formation around Mid-Infrared Bubble N37: Evidence of Cloud-Cloud Collision
Dewangan, L. K.; Ojha, D. K.; Baug, T. +1 more
We have performed a multi-wavelength analysis of a mid-infrared (MIR) bubble N37 and its surrounding environment. The selected 15‧ × 15‧ area around the bubble contains two molecular clouds (N37 cloud; {V}{lsr} ∼ 37-43 km s-1, and C25.29+0.31; {V}{lsr} ∼ 43-48 km s-1) along the line of sight. A total of …
A Giant Lyα Nebula in the Core of an X-Ray Cluster at Z = 1.99: Implications for Early Energy Injection
Dickinson, Mark; Daddi, Emanuele; Vignali, Cristian +17 more
We present the discovery of a giant ≳100 kpc Lyα nebula detected in the core of the X-ray emitting cluster CL J1449+0856 at z = 1.99 through Keck/LRIS narrow-band imaging. This detection extends the known relation between Lyα nebulae and overdense regions of the universe to the dense core of a 5-7 × 1013 M ⊙ cluster. The most…
SHIELD: Comparing Gas and Star Formation in Low-mass Galaxies
McQuinn, Kristen B. W.; Cannon, John M.; Skillman, Evan D. +22 more
We analyze the relationships between atomic, neutral hydrogen (H I) and star formation (SF) in the 12 low-mass SHIELD galaxies. We compare high spectral (∼0.82 km s-1 ch-1) and spatial resolution (physical resolutions of 160-640 pc) H I imaging from the VLA with Hα and far-ultraviolet imaging. We quantify the degree of co-spa…
A Comprehensive Investigation on the Slowing Down of Cosmic Acceleration
Li, Nan; Li, Miao; Wang, Shuang +1 more
Shafieloo et al. first proposed the possibility that the current cosmic acceleration (CA) is slowing down. However, this is rather counterintuitive because a slowing down CA cannot be accommodated in most mainstream cosmological models. In this work, by exploring the evolutionary trajectories of the dark energy equation of state w(z) and decelerat…