Search Publications
Star Cluster Formation and Evolution in M101: An Investigation with the Legacy Extragalactic UV Survey
Sabbi, E.; Dale, D. A.; Calzetti, D. +13 more
We present Hubble Space Telescope WFC3/UVIS (F275W, F336W) and ACS/WFC optical (F435W, F555W, and F814W) observations of the nearby grand-design spiral galaxy M101 as part of the Legacy Extragalactic UV Survey (LEGUS). Compact sources detected in at least four bands were classified by both human experts and the convolutional neural network STARCNE…
New Clues to the Evolution of Dwarf Carbon Stars From Their Variability and X-Ray Emission
Roulston, Benjamin R.; Green, Paul J.; Anderson, Scott F. +6 more
As main-sequence stars with C > O, dwarf carbon (dC) stars are never born alone but inherit carbon-enriched material from a former asymptotic giant branch (AGB) companion. In contrast to M dwarfs in post-mass-transfer binaries, C2 and/or CN molecular bands allow dCs to be identified with modest-resolution optical spectroscopy, even a…
A New Cold Stream near the Southern Galactic Pole
Zhao, Gang; Zhao, Jing-Kun; Yang, Yong +2 more
We report the discovery of a cold stream near the southern Galactic pole (dubbed as SGP-S) detected in Gaia Early Data Release 3. The stream is at a heliocentric distance of ~9.5 kpc and spans nearly 58° by 0.°6 on sky. The color-magnitude diagram of SGP-S indicates an old and metal-poor (age ~12 Gyr, [M/H] ~ -2.0 dex) stellar population. The stre…
Two-point Separation Functions for Modeling Wide Binary Systems in Nearby Dwarf Galaxies
Peñarrubia, Jorge; Koposov, Sergey E.; Walker, Matthew G. +1 more
We use a geometric method to derive (two-dimensional) separation functions among pairs of objects within populations of specified position function ${dN}/d{\boldsymbol{R}}$ . We present analytic solutions for separation functions corresponding to a uniform surface density within a circular field, a Plummer sphere (viewed in projection), and the mi…
Massive Molecular Gas Reservoir in a Luminous Submillimeter Galaxy during Cosmic Noon
Cooray, A.; Marchetti, L.; Nayyeri, H. +11 more
We present multiband observations of an extremely dusty star-forming lensed galaxy (HERS1) at z = 2.553. High-resolution maps of HST/WFC3, SMA, and ALMA show a partial Einstein ring with a radius of ~3″. The deeper HST observations also show the presence of a lensing arc feature associated with a second lens source, identified to be at the same re…
Multi-passband Observations of a Solar Flare over the He I 10830 Å line
Polito, Vanessa; Xu, Yan; Cao, Wenda +5 more
This study presents a C3.0 flare observed by the Big Bear Solar Observatory/Goode Solar Telescope (GST) and Interface Region Imaging Spectrograph (IRIS) on 2018 May 28 around 17:10 UT. The Near-Infrared Imaging Spectropolarimeter of GST was set to spectral imaging mode to scan five spectral positions at ±0.8, ±0.4 Å and line center of He I 10830 Å…
Insights into the Evolution of Five Isolated Galaxies
Wolter, A.; Uslenghi, M.; Marino, A. +3 more
Galaxy evolution is believed to be conditioned by the environment. Isolated galaxies or galaxies in poor groups are an excellent laboratory to study evolutionary mechanisms where effects of the environment are minimal. We present new Swift-UVOT data in six filters, three in the ultraviolet (UV), of five isolated galaxies aiming at shedding light i…
The CO Emission in the Taffy Galaxies (UGC 12914/15) at 60 pc Resolution. I. The Battle for Star Formation in the Turbulent Taffy Bridge
Boulanger, F.; Falgarone, E.; Braine, J. +8 more
We present Atacama Large Millimeter/submillimeter Array observations at a spatial resolution of 0.″2 (60 pc) of CO emission from the Taffy galaxies (UGC 12914/5). The observations are compared with narrowband Paα, mid-IR, radio continuum and X-ray imaging, plus optical spectroscopy. The galaxies have undergone a recent head-on collision, creating …
Ionized Carbon around IRC+10216
Smith, Nathan; Tram, Le Ngoc; Reach, William T. +5 more
Asymptotic giant branch stars create a rich inventory of molecules in their envelopes as they lose mass during later stages of their evolution. These molecules cannot survive the conditions in interstellar space, where they are exposed to ultraviolet photons of the interstellar radiation field. As a result, daughter molecules are the ones injected…
The Ultraviolet C II Lines as a Diagnostic of κ-distributed Electrons in Planetary Nebulae
Zhang, Yong; Yao, Zheng-Wei
Non-Maxwellian κ electron energy distributions (EEDs) have been proposed in recent years to resolve the so-called "electron temperature and abundance discrepancy problem" in the study of planetary nebulae (PNs). Thus the need to develop diagnostic tools to determine from observations the EED of PNs is raised. Arising from high-energy levels, the u…