We use X-ray observations of quasar microlensing (sensitive to smaller compact objects than in the optical) to study the possible presence of a population of low mass black holes (BHs; from ~10-3 M ⊙ to 10-1 M ⊙) in lens galaxies. We compare these observations with microlensing magnification simulations of a mixed population of stars and BHs plus a
Constraints on the Abundance of Primordial Black Holes from X-Ray Quasar Microlensing Observations: Substellar to Planetary Mass RangeEsteban-Gutiérrez, A. et al.92023Citations0
GTC/CanariCam Mid-IR Polarimetry of Magnetic Fields in Star-Forming Region W51 IRS2
We present 0.4 arcsec-resolution mid-IR imaging polarimetry, obtained with CanariCam at GTC, of the central 0.11 pc x 0.28 pc (4.2 arcsec x 10.8 arcsec) region of W51 IRS2. The observed mid-IR polarization across this region is typically several percent, with values as high as 12%. The polarization arises from ensembles of non-spherical silicateSwanson, Pae et al.
Unsupervised Classification of RR Lyrae stars
Big Datasets are becoming more and more prominent in the field of astrophysics with new powerful telescopes and surveys capturing parts of our night sky in an almost continuous fashion. Consequently, unsupervised Machine Learning is key to getting first insight into this abundance of data. We present our results on the performance of unsupervisedSteinwender, Lukas et al.
Long-term multiwavelength monitoring and reverberation mapping of NGC 2617 during a changing-look event
We present the results of photometric and spectroscopic monitoring campaigns of the changing look AGN NGC 2617 carried out from 2016 until 2022 and covering the wavelength range from the X-ray to the near-IR. The facilities included the telescopes of the SAI MSU, MASTER Global Robotic Net, the 2.3-m WIRO telescope, Swift, and others. We foundOknyansky, V. L. et al.
The Pristine dwarf galaxy survey-V. The edges of the dwarf galaxy Hercules
We present a new spectroscopic study of 175 stars in the vicinity of the dwarf galaxy Hercules (d ~ 132 kpc) with data from the Anglo-Australian Telescope and its AAOmega spectrograph together with the Two Degree Field multi-object system to solve the conundrum that whether Hercules is tidally disrupting. We combine broad-band photometry, properLongeard, Nicolas et al.
On the accretion of a new group of galaxies onto Virgo - III. The stellar population radial gradients of dEs
Using MUSE data, we investigate the radial gradients of stellar population properties (namely age, [M/H], and the abundance ratio of α elements [α/Fe]) for a sample of nine dwarf early-type (dE) galaxies with log(M⋆/M⊙) ~ 9.0 and an infall time onto the Virgo cluster of 2-3 Gyr ago. We followed a similar approach as in Bidaran et al. to deriveBidaran, Bahar et al.