Search Publications
Detailed analysis of the variable star population in the globular cluster NGC 7006
Arellano Ferro, A.; Muneer, S.; Bustos Fierro, I. H. +3 more
A 5-yr CCD photometric VI time series of NGC 7006 is employed to perform a detailed analysis of the known population of variable stars. In the process, we have corrected inconsistent classifications, sky coordinates and found 10 new cluster member variables. An independent reddening estimate with a value E(B-V) = 0.08 ± 0.05 is made. Using Fourier…
The nature of 500 micron risers - II. Multiplicities and environments of sub-mm faint dusty star-forming galaxies
Pérez-Fournon, I.; Clements, D. L.; Riechers, D. +6 more
We present Submillimeter Common User Bolometer Array 2 (SCUBA-2) and Submillimeter Array (SMA) follow-up observations of four candidate high-redshift dusty star-forming galaxies, selected as sources with rising spectral energy distributions in the 250, 350, and 500 µm Herschel SPIRE bands. Previous SMA observations showed no counterparts to …
Stellar halo striations from assumptions of axisymmetry
Belokurov, Vasily; Evans, N. Wyn; Davies, Elliot Y. +1 more
Motivated by the Large Magellanic Cloud (LMC)'s impact on the integral of motion space of the stellar halo, we run an N-body merger simulation to produce a population of halo-like stars. We subsequently move to a test-particle simulation, in which the LMC perturbs this debris. When an axisymmetric potential is assumed for the final snapshot of the…
Hubble Space Telescope imaging of the compact elliptical galaxy M32 reveals a dearth of carbon stars
Boyer, M. L.; Meixner, M.; van Loon, J. Th +2 more
We present new Hubble Space Telescope Wide-Field Camera 3/infrared medium-band photometry of the compact elliptical galaxy M32, chemically resolving its thermally pulsating asymptotic giant branch stars. We find 2829 M-type stars and 57 C stars. The carbon stars are likely contaminants from M31. If carbon stars are present in M32 they are so in ve…
The Pristine Inner Galaxy Survey (PIGS) - VI. Different vertical distributions between two DIBs at 442.8 nm and 862.1 nm
Fouesneau, Morgan; Sestito, Federico; Martin, Nicolas F. +8 more
Although diffuse interstellar bands (DIBs) were discovered over 100 yr ago, for most of them, their origins are still unknown. Investigation on the correlations between different DIBs is an important way to study the behaviour and distributions of their carriers. Based on stacking thousands of spectra from the Pristine Inner Galaxy Survey, we stud…
Azimuthal temperature variations in ISO-Oph 2 from multifrequency ALMA observations
Casassus, Simon; Christiaens, Valentin; Ribas, Álvaro +8 more
Environmental effects, such as stellar fly-bys and external irradiation, are thought to affect the evolution of protoplanetary discs in clustered star formation. Previous Atacama Large Millimetre/submillimetre Array (ALMA) images at 225 GHz of the ISO-Oph 2 binary revealed a peculiar morphology in the disc of the primary, perhaps due to a possible…
Calibrating SPI-ACS/INTEGRAL for gamma-ray bursts and re-estimating energetics of GRB/GW 190425 in gamma-ray range
Pozanenko, A. S.; Minaev, P. Yu
SPI-ACS/INTEGRAL is one of the most sensitive orbital gamma-ray detectors in energy range above 80 keV. Since 2002 it registered several thousands of gamma-ray bursts (GRBs), including the bursts associated with LIGO-Virgo gravitational wave events GW 170817 and GW 190425. No dedicated in-flight calibrations were performed for SPI-ACS/INTEGRAL, co…
Catching a Milky Way open cluster in its last breath
Piatti, Andrés E.
Theoretical models have suggested peculiar velocity dispersion profiles of star clusters facing dissolution. They predicted that, besides bound stars that still belong to the star cluster, and unbound ones already stripped off, there is an intermediate population of stars that having acquired the enough energy to escape the cluster are still withi…
Achromatic rapid flares in hard X-rays in the γ-ray binary LS I + 61 303
Romero, Gustavo E.; Saavedra, Enzo A.; Bosch-Ramon, Valenti +1 more
We report on the presence of very rapid hard X-ray variability in the γ-ray binary LS I + 61 303. The results were obtained by analysing Nuclear Spectroscopic Telescope Array (NuSTAR) data, which show two achromatic strong flares on ks time-scales before apastron. The Swift/Burst Alert Telescope orbital X-ray light curve is also presented, and the…
The X-ray variation of M81* resolved by Chandra and NuSTAR
Wang, Q. Daniel; Yuan, Feng; Long, Min +3 more
Despite advances in our understanding of low-luminosity active galactic nuclei (LLAGNs), the fundamental details about the mechanisms of radiation and flare/outburst in hot accretion flow are still largely missing. We have systematically analysed the archival Chandra and NuSTAR X-ray data of the nearby LLAGN M81*, whose Lbol ~ 10-5…