Search Publications
Deep Optical Observations of Unusual Neutron Star Calvera with the GTC
Shibanov, Yury; Danilenko, Andrey; Zharikov, Sergey +2 more
Calvera is an unusual, isolated neutron star with a pure thermal X-ray spectrum typical of central compact objects in supernova remnants. On the other hand, its rotation period and spin-down rate are typical of ordinary rotation-powered pulsars. It was discovered and studied through X-rays, and has not yet been detected in other spectral domains. …
On the Relation between the Mysterious 21 µm Emission Feature of Post-asymptotic Giant Branch Stars and Their Mass-loss Rates
Li, Aigen; Jiang, B. W.; Mishra, Ajay
Over two decades ago, a prominent, mysterious emission band peaking at ∼20.1 µm was serendipitously detected in four preplanetary nebulae (PPNe; also known as “protoplanetary nebulae”). To date, this spectral feature, designated as the “21 µm” feature, has been seen in 27 carbon-rich PPNe in the Milky Way and the Magellanic Clouds. The…
A Star-forming Ring around κ Ori 250 pc from the Sun
Megeath, S. T.; Pillitteri, I.; Wolk, S. J.
X-rays are a powerful probe of activity in early stages of star formation. They allow us to identify young stars even after they have lost the IR signatures of circumstellar disks and provide constraints on their distance. Here, we report on XMM-Newton observations that detect 121 young stellar objects (YSOs) in two fields between L1641 S and κ Or…
A Multiwavelength Characterization of Proto-brown-dwarf Candidates in Serpens
Riaz, B.; Gonzalez-Martin, O.; Caselli, P. +3 more
We present results from a deep submillimeter survey in the Serpens Main and Serpens/G3-G6 clusters, conducted with the Submillimetre Common-User Bolometer Array (SCUBA-2) at the James Clerk Maxwell Telescope. We have combined near- and mid-infrared spectroscopy, Herschel PACS far-infrared photometry, submillimeter continuum, and molecular gas line…
Transverse Velocity Shifts in Protostellar Jets: Rotation or Velocity Asymmetries?
De Colle, Fabio; Riera, Angels; Cerqueira, Adriano H.
Observations of several protostellar jets show systematic differences in radial velocity transverse to the jet propagation direction that have been interpreted as evidence of rotation in the jets. In this paper we discuss the origin of these velocity shifts, and show that they could originate from rotation in the flow, or from side-to-side asymmet…
The Gamma-Ray Source AGL J2241+4454 as the Possible Counterpart of MWC 656
Verrecchia, F.; Sabatini, S.; Pittori, C. +5 more
AGILE discovered the transient source AGL J2241+4454 in 2010, which triggered the study of the associated field allowing for the discovery of the first Be/black hole binary system: MWC 656. This binary was suggested to be the counterpart of AGL J2241+4454, but this association is still not robust. In this work we explore the archival AGILE and Fer…
Departure of High-temperature Iron Lines from the Equilibrium State in Flaring Solar Plasmas
Keenan, F. P.; Kawate, T.; Jess, D. B.
The aim of this study is to clarify if the assumption of ionization equilibrium and a Maxwellian electron energy distribution is valid in flaring solar plasmas. We analyze the 2014 December 20 X1.8 flare, in which the Fe xxi 187 Å, Fe xxii 253 Å, Fe xxiii 263 Å, and Fe xxiv 255 Å emission lines were simultaneously observed by the EUV Imaging Spect…
Detection of HF Toward PKS 1830-211, Search for Interstellar H2F+, and Laboratory Study of H2F+ and H2Cl+ Dissociative Recombination
Muller, S.; Black, J. H.; Miyamoto, Y. +7 more
We report extragalactic observations of two fluorine-bearing species, hydrogen fluoride (HF) and fluoronium (H2F+), in the z = 0.89 absorber in front of the lensed blazar PKS 1830-211 with the Atacama Large Millimeter/submillimeter Array. HF was detected toward both southwest and northeast images of the blazar, with column de…
NuSTAR and XMM-Newton Observations of 1E1743.1-2843: Indications of a Neutron Star LMXB Nature of the Compact Object
Hailey, Charles J.; Mori, Kaya; Zhang, Shuo +13 more
We report on the results of NuSTAR and XMM-Newton observations of the persistent X-ray source 1E1743.1-2843, located in the Galactic Center region. The source was observed between 2012 September and October by NuSTAR and XMM-Newton, providing almost simultaneous observations in the hard and soft X-ray bands. The high X-ray luminosity points to the…
The VIRUS-P Exploration of Nearby Galaxies (VENGA): Radial Gas Inflow and Shock Excitation in NGC 1042
Blanc, Guillermo A.; Jogee, Shardha; Luo, Rongxin +3 more
NGC 1042 is a late-type bulgeless disk galaxy that hosts low-luminosity active galactic nuclei (AGNs) coincident with a massive nuclear star cluster. In this paper, we present the integral field spectroscopy studies of this galaxy, based on the data obtained with the Mitchell spectrograph on the 2.7 m Harlan J. Smith telescope. In the central 100-…