Related papers: Persistent and Transient Blank Field Sources
We consider the gamma-ray spectrum from neutralino dark matter annihilations and show that internal bremsstrahlung of W pair final states gives a previously neglected source of photons at energies near the mass of the neutralino. For masses…
We study the optical variability of a sample of candidate low-mass (dwarf ang Seyfert) active galactic nuclei (AGNs) using Zwicky Transient Facility g-band light curves. Our sample is compiled from broad-line AGNs in dwarf galaxies reported…
The cooling and reheating histories of dim isolated neutron stars(DINs) are discussed. Energy dissipation due to dipole spindown with ordinary and magnetar fields, and due to torques from a fallback disk are considered as alternative…
In spite of rapid experimental progress, windows for light superparticles remain. One possibility is a ~100 GeV tau slepton whose t-channel exchange can give the correct thermal relic abundance for a relatively light neutralino. We…
Central Compact Objects (CCOs) are a handful of soft X-ray sources located close to the centers of Supernova Remnants and supposed to be young, radio-quiet Isolated Neutron Stars (INSs). A clear understanding of their physics would be…
Some evidence for sterile neutrinos has been found in short baseline observations where the measured neutrino flux did not agree with expectations. Systematic uncertainties from the expected values has limited the sensitivity of this…
We study a self-gravitating ultralight dark matter condensate (a boson star) hosting a central black hole, in the nonrelativistic limit, which we refer to as a boson star black hole (BS-BH) system. We numerically solve the equations of…
Neutrinos traveling over cosmic distances are ideal probes of new physics. We leverage on the approaching detection of the diffuse supernova neutrino background (DSNB) to explore whether, if the DSNB showed departures from theoretical…
Deep X-ray surveys have resolved much of the X-ray background radiation below 2 keV into discrete sources, but the background above 8 keV remains largely unresolved. The obscured (type 2) Active Galactic Nuclei (AGNs) that are expected to…
Fast X-ray Transients (FXTs) are X-ray flares with a duration ranging from a few hundred seconds to a few hours. Possible origins include the tidal disruption of a white dwarf by an intermediate-mass black hole, a supernova shock breakout,…
Submillimeter and near-infrared images of cool dusty debris disks and rings suggest the existence of unseen planets. At dusty but non-imaged stars, semi-major axes of associated planets can be estimated from the dust temperature. For some…
We analyze Hubble Space Telescope (HST) optical imaging of eight low-mass galaxies hosting active galactic nuclei (AGN) identified via their photometric variability in \cite{baldassare_search_2020}. We use GALFIT to model the 2D galaxy…
Rotating Radio Transients (RRATs) are a new class of neutron stars discovered through the emission of radio bursts. Eleven sources are known up to now, but population studies predict these objects to be more numerous than the normal radio…
The Herschel very wide-field surveys have charted hundreds of square degrees in multiple far-IR (FIR) bands. While the Sloan Digital Sky Survey (SDSS) is currently the best resource for optical counterpart identifications over such wide…
Motivated by recent claims of lines in the Fermi gamma-ray spectrum, we critically examine means of enhancing neutralino annihilation into neutral gauge bosons. The signal can be boosted while remaining consistent with continuum photon…
We present the second in a series of results in which we have searched for undiscovered neutron stars in supernova remnants (SNRs). This paper deals with the largest six SNRs in our sample, too large for Chandra or XMM-Newton to cover in a…
Over the last decade, X-ray observations unveiled the existence of several classes of isolated neutron stars (INSs) which are radio-quiet or exhibit radio emission with properties much at variance with those of ordinary radio pulsars. The…
We present a sample of 115 very low optical surface brightness, highly extended, HI-rich galaxies carefully selected from the ALFALFA survey that have similar optical absolute magnitudes, surface brightnesses, and radii to recently…
X-ray-dim isolated neutron stars (XDINSs), also known as the Magnificent Seven, exhibits a Planck-like soft X-ray spectrum. In the optical/ultraviolet(UV) band, there is an excess of radiation compared to the extrapolation from the X-ray…
In 2018, we reported our discovery of a dozen quiescent X-ray binaries in the central parsec (pc) of the Galaxy (Hailey et al. 2018). In a recent follow-up paper (Mori et al. 2021), we published an extended analysis of these sources and…