Search Publications
The early B-type star Rho Ophiuchi A is an X-ray lighthouse
Reale, Fabio; Wolk, Scott J.; Pillitteri, Ignazio +1 more
We present the results of a 140 ks XMM-Newton observation of the B2 star ρ Oph A. The star has exhibited strong X-ray variability: a cusp-shaped increase of rate, similar to that which we partially observed in 2013, and a bright flare. These events are separated in time by about 104 ks, which likely correspond to the rotational period of the star …
K2-113: a dense hot-Jupiter transiting a solar analogue
Jordán, Andrés; Espinoza, Néstor; Brahm, Rafael +8 more
We present the discovery of K2-113, a dense hot-Jupiter discovered using photometry from Campaign 8 of the Kepler-2 (K2) mission and high-resolution spectroscopic follow-up obtained with the FEROS spectrograph. The planet orbits a V = 13.68 solar analogue in a P=5.817 60^{+0.000 03}_{-0.000 03} d orbit, and has a radius of 0.93^{+0.10}_{-0.07}R_J …
Pico-charged intermediate particles rescue dark matter interpretation of 511 keV signal
Farzan, Y.; Rajaee, M.
Various alleged indirect dark matter search signals, such as the 511 keV line from galaxy center or the PAMELA/AMS02 signal, are often challenged by the absence of corresponding signal from dwarf galaxies and/or by the absence of an impact on CMB through delayed recombination. We propose a novel scenario that can avoid these bounds based on the de…
Constraints on the Progenitor of SN 2010jl and Pre-existing Hot Dust in its Surrounding Medium
Van Dyk, Schuyler D.; Filippenko, Alexei V.; Kelly, Patrick L. +6 more
A search for the progenitor of SN 2010jl, an unusually luminous core-collapse supernova of Type IIn, using pre-explosion Hubble/WFPC2 and Spitzer/IRAC images of the region, yielded upper limits on the UV and near-infrared (IR) fluxes from any candidate star. These upper limits constrain the luminosity and effective temperature of the progenitor, t…
Abundance Analyses of the New R Coronae Borealis Stars: ASAS-RCB-8 and ASAS-RCB-10
Kamath, Devika; Pandey, Gajendra; Kameswara Rao, N. +3 more
Abundance analyses of the two newly discovered R Coronae Borealis (RCB) stars ASAS-RCB-8 and ASAS-RCB-10 were conducted using high-resolution optical spectra and model atmospheres. Their chemical compositions place the pair among the majority class of RCBs. ASAS-RCB-10 is one of the most N-poor majority RCBs with an above average O abundance. Rela…
Origin of X-rays in the low state of the FSRQ 3C 273: evidence of inverse Compton emission
Gupta, Alok C.; Wiita, Paul J.; Dewangan, Gulab C. +2 more
We analyse the 2.5-10 keV X-ray spectra of the luminous quasar 3C 273 and simultaneous observations in UV wavelengths from XMM-Newton between 2000 and 2015. The lowest flux level ever was observed in 2015. The continuum emission from 3C 273 is generally best described by an absorbed power-law but during extremely low states the addition of fluores…
The discrepancy between dynamical and theoretical mass in the triplet-system 2MASS J10364483+1521394
Henning, Thomas; Brandner, Wolfgang; Calissendorff, Per +6 more
We combine new Lucky Imaging astrometry from New Technology Telescope/AstraLux Sur with already published astrometry from the AstraLux Large M-dwarf Multiplicity Survey to compute orbital elements and individual masses of the 2MASS J10364483+1521394 triple system belonging to the Ursa-Major moving group. The system consists of one primary low-mass…
A hard-to-soft state transition of Aquila X-1 observed with Suzaku
Yamaoka, Kazutaka; Makishima, Kazuo; Nakazawa, Kazuhiro +3 more
The recurrent soft X-ray transient Aquila X-1 was observed with Suzaku for a gross duration of 79.9 ks, on 2011 October 21 when the object was in a rising phase of an outburst. During the observation, the source exhibited a clear spectral transition from the hard state to the soft state, on a time scale of ∼30 ks. Across the transition, the 0.8-10…
The Canonical Luminous Blue Variable AG Car and Its Neighbor Hen 3-519 are Much Closer than Previously Assumed
Smith, Nathan; Stassun, Keivan G.
The strong mass loss of Luminous Blue Variables (LBVs) is thought to play a critical role in massive-star evolution, but their place in the evolutionary sequence remains debated. A key to understanding their peculiar instability is their high observed luminosities, which often depends on uncertain distances. Here we report direct distances and spa…
Identification of IGR J01217-7257 with the transient SMC pulsar XTE J0119-731 (SXP 2.16) using XMM-Newton
Haberl, F.; Vasilopoulos, G.; Maggi, P.
The transient IGR J01217-7257 in the Small Magellanic Cloud was found to be in a new outburst during INTEGRAL observations. We triggered an XMM-Newton target of opportunity observation near outburst maximum, which lead to the discovery of X-ray pulsations with a period of 2.165 s. This period is very similar to that detected from XTE J0119-731, su…