Search Publications
Hiding in Plain Sight: Record-breaking Compact Stellar Systems in the Sloan Digital Sky Survey
Janz, Joachim; Forbes, Duncan A.; Romanowsky, Aaron J. +10 more
Motivated by the recent, serendipitous discovery of the densest known galaxy, M60-UCD1, we present two initial findings from a follow-up search, using the Sloan Digital Sky Survey, Subaru/Suprime-Cam, and Hubble Space Telescope imaging, and SOuthern Astrophysical Research (SOAR)/Goodman spectroscopy. The first object discovered, M59-UCD3, has a si…
Characterization of the Inner Knot of the Crab: The Site of the Gamma-Ray Flares?
Weisskopf, Martin C.; Tennant, Allyn; Caraveo, Patrizia +18 more
A particularly intriguing recent result from γ-ray astronomy missions is the detection of powerful flares from the Crab Nebula, which challenges the current understanding of pulsar wind nebulae and acceleration mechanisms. To search for the production site(s) of these flares, we conducted a multi-wavelength observing campaign using Keck, the Hubbl…
A Herschel Study of 24 µµm-Selected AGNs and Their Host Galaxies
Smith, G. P.; Egami, E.; Rieke, G. H. +3 more
We present a sample of 290 24 µm-selected active galactic nuclei (AGNs) mostly at z ∼ 0.3-2.5, within 5.2 {{deg}}2 distributed as 25\prime × 25\prime fields around each of 30 galaxy clusters in the Local Cluster Substructure Survey. The sample is nearly complete to 1 mJy at 24 µm, and has a rich multiwavelength set of ancill…
Observed trend in the star formation history and the dark matter fraction of galaxies at redshift z ≈ 0.8
Cappellari, Michele; Shetty, Shravan
We study the star formation history for a sample of 154 galaxies with stellar mass 10^{10}≲ M_{*} ≲ 10^{12} { M_{⊙}} in the redshift range 0.7 < z < 0.9. We do this using stellar population models combined with full-spectrum fitting of good quality spectra and high-resolution photometry. For a subset of 68 galaxies (M_{*}≳ 10^{11}{ M_{⊙}}) w…
Herschel Observations of Extra-ordinary Sources: Analysi sof the HIFI 1.2 THz Wide Spectral Survey toward Orion KL II. Chemical Implications
Favre, C.; Bergin, E. A.; Crockett, N. R. +5 more
We present chemical implications arising from spectral models fit to the Herschel/HIFI spectral survey toward the Orion Kleinmann-Low nebula (Orion KL). We focus our discussion on the eight complex organics detected within the HIFI survey utilizing a novel technique to identify those molecules emitting in the hottest gas. In particular, we find th…
Proper Motions in Terzan 5: Membership of the Multi-iron Subpopulations and First Constraint on the Orbit
Dalessandro, E.; Massari, D.; Rich, R. M. +6 more
By exploiting two sets of high-resolution images obtained with the Hubble Space Telescope Advanced Camera for Surveys/Wide Field Channel over a baseline of ∼10 years, we have measured relative proper motions (PMs) of ∼70,000 stars in the stellar system Terzan 5. The results confirm the membership of the three subpopulations with different iron abu…
A Two-ribbon White-light Flare Associated with a Failed Solar Eruption Observed by ONSET, SDO, and IRIS
Cheng, X.; Ding, M. D.; Chen, P. F. +4 more
Two-ribbon brightenings are one of the most remarkable characteristics of an eruptive solar flare and are often used to predict the occurrence of coronal mass ejections (CMEs). Nevertheless, it was recently called into question whether all two-ribbon flares are eruptive. In this paper, we investigate a two-ribbon-like white-light (WL) flare that i…
A distinct magnetic property of the inner penumbral boundary. Formation of a stable umbra-penumbra boundary in a sunspot
Jurčák, J.; Bello González, N.; Schlichenmaier, R. +1 more
Context. A sunspot emanates from a growing pore or protospot. In order to trigger the formation of a penumbra, large inclinations at the outskirts of the protospot are necessary. The penumbra develops and establishes by colonising both umbral areas and granulation. Evidence for a unique stable boundary value for the vertical component of the magne…
Multiband variability in the blazar 3C 273 with XMM-Newton
Bhagwan, Jai; Gupta, Alok C.; Wiita, Paul J. +2 more
We have undertaken a nearly simultaneous optical/UV and X-ray variability study of the flat spectrum radio quasar, 3C 273 using data available from the XMM-Newton satellite mission from 2000 June to 2012 July. Here, we focus on the multiwavelength flux variability on both intra-day and long time-scales of this very well known radio-loud source. We…
Formation and Eruption of a Small Flux Rope in the Chromosphere Observed by NST, IRIS, and SDO
Wang, Haimin; Yurchyshyn, Vasyl; Kumar, Pankaj +1 more
Using high-resolution images from the 1.6 m New Solar Telescope at Big Bear Solar Observatory, we report the direct evidence of chromospheric reconnection at the polarity inversion line between two small opposite polarity sunspots. Small jetlike structures (with velocities of ∼20-55 km s-1) were observed at the reconnection site before …