Search Publications

Discovery of a recurrent spectral evolutionary cycle in the ultra-luminous X-ray sources Holmberg II X-1 and NGC 5204 X-1
DOI: 10.1051/0004-6361/202140781 Bibcode: 2021A&A...654A..10G

Vasilopoulos, G.; Godet, O.; Webb, N. A. +2 more

Context. Most ultra-luminous X-ray sources (ULXs) are now thought to be powered by stellar-mass compact objects accreting at super-Eddington rates. While the discovery of evolutionary cycles have marked a breakthrough in our understanding of the accretion flow changes in the sub-Eddington regime in Galactic black hole binaries, their evidence in t…

2021 Astronomy and Astrophysics
XMM-Newton eHST 22
X-ray bounds on cooling, composition, and magnetic field of the Cassiopeia A neutron star and young central compact objects
DOI: 10.1093/mnras/stab2081 Bibcode: 2021MNRAS.506.5015H

Ho, Wynn C. G.; Kaplan, D. L.; Heinke, Craig O. +3 more

We present analysis of multiple Chandra and XMM-Newton spectra, separated by 9-19 yr, of four of the youngest central compact objects (CCOs) with ages <2500 yr: CXOU J232327.9+584842 (Cassiopeia A), CXOU J160103.1-513353 (G330.2+1.0), 1WGA J1713.4-3949 (G347.3-0.5), and XMMU J172054.5-372652 (G350.1-0.3). By fitting these spectra with thermal m…

2021 Monthly Notices of the Royal Astronomical Society
XMM-Newton 22
Investigating the Nature of MGRO J1908+06 with Multiwavelength Observations
DOI: 10.3847/2041-8213/abf925 Bibcode: 2021ApJ...913L..33L

Torres, Diego F.; Li, Jian; Kerr, Matthew +7 more

The unidentified TeV source MGRO J1908+06, with emission extending from hundreds of GeV to beyond 100 TeV, is one of the most intriguing sources in the Galactic plane. MGRO J1908+06 spatially associates with an IceCube hotspot of neutrino emission. Although the hotspot is not significant yet, this suggests a possible hadronic origin of the observe…

2021 The Astrophysical Journal
XMM-Newton 22
Scalar dark matter candidates revisited
DOI: 10.1103/PhysRevD.103.075005 Bibcode: 2021PhRvD.103g5005B

Pradler, Josef; BÅ`hm, Céline; Chu, Xiaoyong +1 more

We revisit the possibility of light-scalar dark matter, in the MeV to GeV mass bracket and coupled to electrons through fermion or vector mediators, in light of significant experimental and observational advances that probe new physics below the GeV scale. We establish new limits from electron colliders and fixed-target beams and derive the streng…

2021 Physical Review D
INTEGRAL 22
A Differential Measurement of Circumstellar Extinction for AA Tau's 2011 Dimming Event
DOI: 10.3847/1538-3881/abcc73 Bibcode: 2021AJ....161...61C

Manara, C. F.; Covey, K. R.; Herczeg, G. J. +1 more

AA Tau is a classical T Tauri star with a highly inclined, warped circumstellar disk. For decades, AA Tau exhibited photometric and spectroscopic variabilities that were successfully modeled as occultations of the primary star by circumstellar material. In 2011, AA Tau entered an extended faint state, presumably due to enhanced levels of circumste…

2021 The Astronomical Journal
eHST 22
Optical Analysis and Modeling of HD96670, a New Black Hole X-Ray Binary Candidate
DOI: 10.3847/1538-4357/abf24c Bibcode: 2021ApJ...913...48G

Gomez, Sebastian; Grindlay, Jonathan E.

We report on optical observations and modeling of HD96670, a single-line spectroscopic binary in the Carina OB2 association. We collected 10 epochs of optical spectroscopy, and optical photometry on 17 nonconsecutive nights on the source. We construct a radial velocity curve from the spectra, and update the orbital period of the binary to be P = 5…

2021 The Astrophysical Journal
XMM-Newton 22
The Polar Cusp Seen by Cluster
DOI: 10.1029/2021JA029582 Bibcode: 2021JGRA..12629582P

Pitout, F.; Bogdanova, Y. V.

The investigation of the magnetospheric polar cusps was one of the main objectives of the Cluster mission. The four satellites have crossed those regions numerous times over the years and, with their suitable instrumentation, favorable orbits, and unique multipoint measurements, many aspects of the cusp have been unveiled. The first of those is it…

2021 Journal of Geophysical Research (Space Physics)
Cluster 22
UOCS. IV. Discovery of diverse hot companions to blue stragglers in the old open cluster King 2
DOI: 10.1007/s12036-021-09746-y Bibcode: 2021JApA...42...89J

Jadhav, Vikrant V.; Subramaniam, Annapurni; Pandey, Sindhu +1 more

King 2, one of the oldest clusters in the Milky Way, with an age of 6 Gyr and distance of 5700 pc, has been observed with UVIT payload on the AstroSat. With membership information deriv…

2021 Journal of Astrophysics and Astronomy
Gaia 22
Initial Characterization of Active Transitioning Centaur, P/2019 LD2 (ATLAS), Using Hubble, Spitzer, ZTF, Keck, Apache Point Observatory, and GROWTH Visible and Infrared Imaging and Spectroscopy
DOI: 10.3847/1538-3881/abd94b Bibcode: 2021AJ....161..116B

Duev, Dmitry A.; Riddle, Reed; Horner, Jonathan +43 more

We present visible and mid-infrared imagery and photometry of temporary Jovian co-orbital comet P/2019 LD2 taken with Hubble Space Telescope/Wide Field Camera 3 (HST/WFC3), Spitzer Space Telescope/Infrared Array Camera (Spitzer/IRAC), and the GROWTH telescope network, visible spectroscopy from Keck/Low-Resolution Imaging Spectrometer (L…

2021 The Astronomical Journal
Gaia eHST 22
Gravity Wave Activity in the Martian Atmosphere at Altitudes 20-160 km From ACS/TGO Occultation Measurements
DOI: 10.1029/2021JE006899 Bibcode: 2021JGRE..12606899S

Montmessin, Franck; Starichenko, Ekaterina D.; Belyaev, Denis A. +7 more

The paper presents observations of gravity wave-induced temperature disturbances in the Martian atmosphere obtained with the mid-infrared (MIR) spectrometer, a channel of the Atmospheric Chemistry Suite instrument on board the Trace Gas Orbiter (ACS/TGO). Solar occultation measurements of a CO2 absorption band at 2.7 µm were used for retriev…

2021 Journal of Geophysical Research (Planets)
ExoMars-16 22