Search Publications
A UV-to-NIR Study of Molecular Gas in the Dust Cavity around RY Lupi
France, K.; Alcalá, J. M.; Williams, J. P. +10 more
We present a study of molecular gas in the inner disk (r< 20 {au}) around RY Lupi, with spectra from HST-COS, HST-STIS, and VLT-CRIRES. We model the radial distribution of flux from hot gas in a surface layer between r = 0.1-10 au, as traced by Lyα-pumped H2. The result shows H2 emission originating in a ring centered at ∼…
An Unexpected Detection of Bifurcated Blue Straggler Sequences in the Young Globular Cluster NGC 2173
Deng, Licai; de Grijs, Richard; Li, Chengyuan +2 more
The bifurcated patterns in the color-magnitude diagrams of blue straggler stars (BSSs) have attracted significant attention. This type of special (but rare) pattern of two distinct blue straggler sequences is commonly interpreted as evidence that cluster core-collapse-driven stellar collisions are an efficient formation mechanism. Here, we report …
Mapping Lyman Continuum Escape in Tololo 1247-232
Jaskot, Anne E.; James, Bethan L.; Oey, M. S. +2 more
Low-redshift, spatially resolved Lyman continuum (LyC) emitters allow us to clarify the processes for LyC escape from these starburst galaxies. We use Hubble Space Telescope (HST) WFC3 and ACS imaging of the confirmed low-redshift LyC emitter Tol 1247-232 to study the ionization structure of the gas and its relation to the ionizing star clusters. …
Herschel PACS Observations of 4-10 Myr Old Classical T Tauri Stars in Orion OB1
Qi, Chunhua; Calvet, Nuria; Espaillat, Catherine C. +12 more
We present Herschel PACS observations of eight classical T Tauri Stars in the ∼7-10 Myr old OB1a and the ∼4-5 Myr old OB1b Orion subassociations. Detailed modeling of the broadband spectral energy distributions, particularly the strong silicate emission at 10 µm, shows that these objects are (pre-)transitional disks with some amount of small…
Asteroseismology of the Double-mode High-amplitude δ Scuti Star VX Hydrae
Fu, Jian-Ning; Su, Jie; Castro, A. +11 more
Bi-site time-series photometric and high-resolution spectroscopic observations were made for the double-mode high-amplitude δ Scuti star VX Hya. The fundamental frequency f 0 = 4.4763 c days-1, the first overtone f 1 = 5.7897 c days-1, and 23 harmonics and linear combinations of f 0 and f
Where is the Engine Hiding Its Missing Energy? Constraints from a Deep X-Ray Non-detection of the Superluminous SN 2015bn
Berger, Edo; Chornock, Ryan; Margutti, Raffaella +5 more
SN 2015bn is a nearby hydrogen-poor superluminous supernova (SLSN-I) that has been intensively observed in X-rays with the goal to detect the spindown powered emission from a magnetar engine. The early-time ultraviolet/optical/infrared (UVOIR) data fit well to the magnetar model, but require leakage of energy at late times of ≲1043 erg …
Lithium and Beryllium Isotopes with the PAMELA Experiment
Castellini, G.; Sarkar, R.; Ricci, M. +56 more
The cosmic ray (CR) lithium and beryllium (6Li, 7Li, 7Be, 9Be, 10Be) isotopic composition has been measured with the satellite-borne experiment PAMELA, which was launched into low-Earth orbit on board the Resurs-DK1 satellite on 2006 June 15. The rare lithium and beryllium isotopes in CRs are …
Mapping Circumstellar Matter with Polarized Light: The Case of Supernova 2014J in M82
Baade, Dietrich; Sparks, William B.; Wang, Lifan +11 more
Optical polarimetry is an effective way of probing the environment of a supernova for dust. We acquired linear HST ACS/WFC polarimetry in bands F475W, F606W, and F775W of the supernova (SN) 2014J in M82 at six epochs from ∼277 days to ∼1181 days after the B-band maximum. The polarization measured at day 277 shows conspicuous deviations from other …
A Deep Pulse Search in 11 Low Mass X-Ray Binaries
Messenger, C.; Wette, K.; Patruno, A.
We present a systematic coherent X-ray pulsation search in 11 low mass X-ray binaries (LMXBs). We select a relatively broad variety of LMXBs, including persistent and transient sources, spanning orbital periods between 0.3 and 17 hr. We use about 3.6 Ms of data collected by the Rossi X-Ray Timing Explorer and XMM-Newton and apply a semi-coherent s…
Coordinated Assembly of Brightest Cluster Galaxies
Conroy, Charlie; Brammer, Gabriel; Gu, Meng
Brightest Cluster Galaxies (BCGs) in massive dark matter halos are shaped by complex merging processes. We present a detailed stellar population analysis in the central region of Abell 3827 at z ∼ 0.1, including five-nucleus galaxies involved in a BCG assembly. Based on deep spectroscopy from the Multi Unit Spectroscopic Explorer, we fit the optic…