Search Publications
Probing Dynamical Processes in the Planet-forming Region with Dust Mineralogy
Manoj, P.; Watson, D. M.; Sargent, B. +6 more
We present Herschel Space Observatory PACS spectra of GQ Lup, a protoplanetary disk in the Lupus star-forming region. Through spectral energy distribution fitting from 0.3 µm to 1.3 mm, we construct a self-consistent model of this system's temperature and density structures, finding that although it is 3 Myr old, its dust has not settled to …
Hubble Space Telescope survey of the Perseus cluster - IV. Compact stellar systems in the Perseus cluster core and ultracompact dwarf formation in star-forming filaments
Conselice, Christopher J.; Penny, Samantha J.; Forbes, Duncan A.
We present the results of the first search for ultracompact dwarfs (UCDs) in the Perseus cluster core, including the region of the cluster around the unusual brightest cluster galaxy NGC 1275. Utilizing Hubble Space Telescope Advanced Camera for Surveys imaging, we identify a sample of 84 UCD candidates with half-light radii 10 < re …
The Dynamics and Heating of Active Region Loops
Doschek, G. A.
I examine the dynamics of active regions using spectra obtained by the Extreme-ultraviolet Imaging Spectrometer (EIS) on the Hinode spacecraft. I show the relationship between non-thermal velocities, Doppler outflows and downflows, intensities, and electron density for two representative active regions out of a group of 18 active regions examined.…
Energy-dependent orbital modulation of X-rays and constraints on emission of the jet in Cyg X-3
Maitra, Chandreyee; Zdziarski, Andrzej A.; Misra, Ranjeev +2 more
We study the orbital modulation of X-rays from Cyg X-3, using data from Swift, INTEGRAL and RXTE. Using the wealth of data presently available and an improved averaging method, we obtain energy-dependent folded and averaged light curves with unprecedented accuracy. We find that above ∼5 keV the modulation depth decreases with increasing energy, wh…
Identifying ultra-cool dwarfs at low Galactic latitudes: a southern candidate catalogue
Marocco, F.; Pinfield, D. J.; Jones, H. R. A. +6 more
We present an ultra-cool dwarf (UCD) catalogue compiled from low southern Galactic latitudes and mid-plane, from a cross-correlation of the Two Micron All-Sky Survey (2MASS) and the SuperCOSMOS survey. The catalogue contains 246 members identified from 5042 deg2 within 220° ≤ ℓ ≤ 360° and 0° < ℓ ≤ 30°, for |b| ≤ 15°. Sixteen candidat…
The Hubble Space Telescope Cluster Supernova Survey. VI. The Volumetric Type Ia Supernova Rate
Gladders, M. D.; Panagia, N.; Huang, X. +41 more
We present a measurement of the volumetric Type Ia supernova (SN Ia) rate out to z ~= 1.6 from the Hubble Space Telescope Cluster Supernova Survey. In observations spanning 189 orbits with the Advanced Camera for Surveys we discovered 29 SNe, of which approximately 20 are SNe Ia. Twelve of these SNe Ia are located in the foregrounds and background…
Deep Chandra observation of the galaxy cluster WARPJ1415.1+3612 at z =1 . An evolved cool-core cluster at high redshift
Tozzi, P.; Rosati, P.; Nonino, M. +2 more
Aims: Using the deepest (370 ks) Chandra observation of a high-redshift galaxy cluster, we perform a detailed characterization of the intra-cluster medium (ICM) of WARPJ1415.1+3612 at z = 1.03, particularly its core region. We also explore the connection between the ICM core properties and the radio/optical properties of the brightest cluster…
Extended soft X-ray emission in 3CR radio galaxies at z < 0.3: high excitation and broad line galaxies
Macchetto, F. D.; Capetti, A.; Grandi, P. +11 more
We analyze Chandra observations of diffuse soft X-ray emission associated with a complete sample of 3CR radio galaxies at z < 0.3. We focus on the properties of the spectroscopic sub-classes of high excitation galaxies (HEGs) and broad line objects (BLOs). Among the 33 HEGs we detect extended (or possibly extended) emission in about 40% of the …
On the Force-free Nature of Photospheric Sunspot Magnetic Fields as Observed from Hinode (SOT/SP)
Tiwari, Sanjiv Kumar
A magnetic field is force-free if there is no interaction between it and the plasma in the surrounding atmosphere, i.e., electric currents are aligned with the magnetic field, giving rise to zero Lorentz force. The computation of various magnetic parameters, such as magnetic energy (using the virial theorem), gradient of twist of sunspot magnetic …
On the Origin of the Supergiant H I Shell and Putative Companion in NGC 6822
Cannon, John M.; Dolphin, Andrew E.; Skillman, Evan D. +6 more
We present new Hubble Space Telescope Advanced Camera for Surveys imaging of six positions spanning 5.8 kpc of the H I major axis of the Local Group dIrr NGC 6822, including both the putative companion galaxy and the large H I hole. The resulting deep color-magnitude diagrams show that NGC 6822 has formed >50% of its stars in the last ~5 Gyr. T…