Search Publications
Discovery of a keV-X-ray excess in RX J1856.5-3754
Yoneyama, Tomokage; Hayashida, Kiyoshi; Nakajima, Hiroshi +2 more
RX J1856.5-3754 is the brightest and nearest (∼120 pc) source among thermally emitting isolated neutron stars. Its spectra observed with XMM-Newton and Chandra satellites are well-fitted with the two-temperature (kT∞ ∼ 32 and 63 eV) blackbody model. Fitting ten sets of the data from Suzaku XIS 0, XIS 1, XIS 3, and XMM-Newton EPIC-pn wit…
Statistics of the fractional polarization of extragalactic dusty sources in Planck HFI maps
Bonavera, L.; González-Nuevo, J.; Toffolatti, L. +2 more
We estimate the average fractional polarization at 143, 217 and 353 GHz of a sample of 4697 extragalactic dusty sources by applying stacking technique. The sample is selected from the second version of the Planck Catalogue of Compact Sources at 857 GHz, avoiding the region inside the Planck Galactic mask (fsky ∼ 60 per cent). We recover…
Sixteen years of X-ray monitoring of Sagittarius A*: Evidence for a decay of the faint flaring rate from 2013 August, 13 months before a rise in the bright flaring rate
Grosso, Nicolas; Mossoux, Enmanuelle
Context. X-ray flaring activity from the closest supermassive black hole Sagittarius A* (Sgr A*) located at the center of our Galaxy has been observed since 2000 October 26 thanks to the current generation of X-ray facilities. In a study of X-ray flaring activity from Sgr A* using Chandra and XMM-Newton public observations from 1999 to 2014 and Sw…
Photographic observations of Saturn's moons at the MAO NAS of Ukraine in 1961–1990
Andruk, V. M.; Pakuliak, L. K.; Yizhakevych, O. M.
A catalog of 1385 astrometric positions of Saturn's moons S2–S9 has been compiled with Tycho-2 as a reference frame from photographic observations obtained at the Main Astronomical Observatory, National Academy of Sciences of Ukraine, in 1961–1990. Astronegatives have been digitized with an Epson Expression 10000XL commercial scanner in 16-bit gra…
A multiwavelength observation and investigation of six infrared dark clouds
Zhang, Chuan-Peng; Li, Guang-Xing; Wang, Jun-Jie +2 more
Context. Infrared dark clouds (IRDCs) are ubiquitous in the Milky Way, yet they play a crucial role in breeding newly-formed stars.
Aims: With the aim of further understanding the dynamics, chemistry, and evolution of IRDCs, we carried out multiwavelength observations on a small sample.
Methods: We performed new observations with the IRA…
A test for skewed distributions of dark matter, and a possible detection in galaxy cluster Abell 3827
Massey, Richard; Taylor, Peter; Jauzac, Mathilde +4 more
Simulations of self-interacting dark matter predict that dark matter should lag behind galaxies during a collision. If the interaction is mediated by a high-mass force carrier, the distribution of dark matter can also develop asymmetric dark matter tails. To search for this asymmetry, we compute the gravitational lensing properties of a mass distr…
A New Approach to Convective Core Overshooting: Probabilistic Constraints from Color-Magnitude Diagrams of LMC Clusters
Williams, Benjamin F.; Johnson, L. Clifton; Dolphin, Andrew +7 more
We present a framework to simultaneously constrain the values and uncertainties of the strength of convective core overshooting, metallicity, extinction, distance, and age in stellar populations. We then apply the framework to archival Hubble Space Telescope observations of six stellar clusters in the Large Magellanic Cloud that have reported ages…
A Ulysses Detection of Secondary Helium Neutrals
Wood, Brian E.; Müller, Hans-Reinhard; Witte, Manfred
The Interstellar Boundary EXplorer (IBEX) mission has recently studied the flow of interstellar neutral He atoms through the solar system and discovered the existence of a secondary He flow that likely originates in the outer heliosheath. We find evidence for this secondary component in Ulysses data. By coadding hundreds of Ulysses He beam maps to…
Very Low-mass Stars and Brown Dwarfs in Upper Scorpius Using Gaia DR1: Mass Function, Disks, and Kinematics
Scholz, Aleks; Cook, Neil J.; Jayawardhana, Ray
Our understanding of the brown dwarf population in star-forming regions is dependent on knowing distances and proper motions and therefore will be improved through the Gaia space mission. In this paper, we select new samples of very low-mass objects (VLMOs) in Upper Scorpius using UKIDSS colors and optimized proper motions calculated using Gaia DR…
Masses of the Planetary Nebula Central Stars in the Galactic Globular Cluster System from HST Imaging and Spectroscopy
Bond, Howard E.; De Marco, Orsola; Lanz, Thierry +4 more
The globular cluster (GC) system of our Galaxy contains four planetary nebulae (PNe): K 648 (or Ps 1) in M15, IRAS 18333-2357 in M22, JaFu 1 in Pal 6, and JaFu 2 in NGC 6441. Because single-star evolution at the low stellar mass of present-epoch GCs was considered incapable of producing visible PNe, their origin presented a puzzle. We imaged the P…