Search Publications
The Resolved Distributions of Dust Mass and Temperature in Local Group Galaxies
Sandstrom, Karin M.; Leroy, Adam K.; Chiang, I-Da +2 more
We utilize archival far-infrared maps from the Herschel Space Observatory in four Local Group galaxies (Small and Large Magellanic Clouds (SMC and LMC), M31, and M33). We model their spectral energy distribution from 100 to 500 µm using a single-temperature modified blackbody emission with a fixed emissivity index of β = 1.8. From the best-f…
UVIT Open Cluster Study. I. Detection of a White Dwarf Companion to a Blue Straggler in M67: Evidence of Formation through Mass Transfer
Jadhav, Vikrant V.; Puzia, Thomas H.; Simunovic, Mirko +7 more
The old open cluster M67, populated with blue straggler stars (BSSs), is a well-known test bed to study the BSS formation pathways. Here, we report the first direct detection of a white dwarf (WD) companion to a BSS in M67, using far-UV images from the Ultra-Violet Imaging telescope on ASTROSAT. Near-simultaneous observations in three far-UV bands…
PAHs as tracers of the molecular gas in star-forming galaxies
Daddi, E.; Elbaz, D.; Gómez-Guijarro, C. +12 more
We combine new CO(1-0) line observations of 24 intermediate redshift galaxies (0.03 < z < 0.28) along with literature data of galaxies at 0 < z < 4 to explore scaling relations between the dust and gas content using polycyclic aromatic hydrocarbon (PAH) 6.2 µm (L6.2), CO (L^' }_CO), and infrared (LIR) lumino…
Space Telescope and Optical Reverberation Mapping Project. VIII. Time Variability of Emission and Absorption in NGC 5548 Based on Modeling the Ultraviolet Spectrum
Im, M.; Malkan, M. A.; Geier, S. +164 more
We model the ultraviolet spectra of the Seyfert 1 galaxy NGC 5548 obtained with the Hubble Space Telescope during the 6 month reverberation mapping campaign in 2014. Our model of the emission from NGC 5548 corrects for overlying absorption and deblends the individual emission lines. Using the modeled spectra, we measure the response to continuum v…
Carbon depletion observed inside T Tauri inner rims. Formation of icy, kilometer size planetesimals by 1 Myr
McClure, M. K.
Context. The carbon content of protoplanetary disks is an important parameter to characterize planets formed at different disk radii. There is some evidence from far-infrared and submillimeter observations that gas in the outer disk is depleted in carbon, with a corresponding enhancement of carbon-rich ices at the disk midplane. Observations of th…
Three-dimensional modeling of chromospheric spectral lines in a simulated active region
Cheung, Mark C. M.; Rempel, Matthias; Danilovic, Sanja +4 more
Context. Because of the complex physics that governs the formation of chromospheric lines, interpretation of solar chromospheric observations is difficult. The origin and characteristics of many chromospheric features are, because of this, unresolved.
Aims: We focus on studying two prominent features: long fibrils and flare ribbons. To model …
Distant Comet C/2017 K2 and the Cohesion Bottleneck
Mutchler, Max; Jewitt, David; Agarwal, Jessica +3 more
The distant long-period comet C/2017 K2 (PANSTARRS) has been outside the planetary region of the solar system for ∼3 Myr, negating the possibility that heat retained from the previous perihelion could be responsible for its activity. This inbound comet is also too cold for water ice to sublimate and too cold for amorphous water ice, if present, to…
Buried Black Hole Growth in IR-selected Mergers: New Results from Chandra
Ellison, Sara L.; Ricci, Claudio; Blecha, Laura +8 more
Observations and theoretical simulations suggest that a significant fraction of merger-triggered accretion onto supermassive black holes is highly obscured, particularly in late-stage galaxy mergers, when the black hole is expected to grow most rapidly. Starting with the Wide-Field Infrared Survey Explorer all-sky survey, we identified a populatio…
Comparing the Quenching Times of Faint M31 and Milky Way Satellite Galaxies
Lewis, Geraint F.; Dolphin, Andrew E.; Skillman, Evan D. +8 more
We present the star formation histories (SFHs) of 20 faint M31 satellites (-12 ≲ M V ≲ -6) that were measured by modeling sub-horizontal branch depth color-magnitude diagrams constructed from Hubble Space Telescope (HST) imaging. Reinforcing previous results, we find that virtually all galaxies quenched between 3 and 9 Gyr ago, indepe…
The EREBOS project: Investigating the effect of substellar and low-mass stellar companions on late stellar evolution. Survey, target selection, and atmospheric parameters
Geier, S.; Dreizler, S.; Heber, U. +14 more
Eclipsing post-common-envelope binaries are highly important for resolving the poorly understood, very short-lived common-envelope phase of stellar evolution. Most hot subdwarfs (sdO/Bs) are the bare helium-burning cores of red giants that have lost almost all of their hydrogen envelope. This mass loss is often triggered by common-envelope interac…