Search Publications
A census of X-ray millisecond pulsars in globular clusters
Zhao, Jiaqi; Heinke, Craig O.
We present a comprehensive census of X-ray millisecond pulsars (MSPs) in 29 Galactic globular clusters (GCs), including 68 MSPs with confirmed X-ray luminosities and 107 MSPs with X-ray upper limits. We compile previous X-ray studies of GC MSPs, and add new analyses of six MSPs (PSRs J1326-4728A, J1326-4728B, J1518+0204C, J1717+4308A, J1737-0314A,…
The complex stellar system M 22: confirming abundance variations with high precision differential measurements
Milone, A. P.; Marino, A. F.; Legnardi, M. V. +8 more
M 22 (NGC 6656) is a chemically complex globular cluster-like system reported to harbour heavy element abundance variations. However, the extent of these variations and the origin of this cluster is still debated. In this work, we investigate the chemical in-homogeneity of M 22 using differential line-by-line analysis of high-quality (R = 110 000,…
A Gaia EDR3 search for tidal tails in disintegrating open clusters
Vaidya, Kaushar; Rao, Khushboo K.; Agarwal, Manan +2 more
We carry out a search for tidal tails in a sample of open clusters with known relatively elongated morphology. We identify the member stars of these clusters from the precise astrometric and deep photometric data from Gaia Early Data Release 3 using the robust membership determination algorithm, ML-MOC. We identify 46 open clusters having a stella…
Multiscale magnetic fields in the central molecular zone: inference from the gradient technique
Wang, Q. Daniel; Lazarian, A.; Hu, Yue
The central molecular zone (CMZ) plays an essential role in regulating the nuclear ecosystem of our Galaxy. To get an insight into magnetic fields of the CMZ, we employ the gradient technique (GT), which is rooted in the anisotropy of magnetohydrodynamic turbulence. Our analysis is based on the data of multiple wavelengths, including molecular emi…
Luminosity functions of globular clusters in five nearby spiral galaxies using HST/ACS images
Mayya, Y. D.; Rosa-González, D.; Rodríguez-Merino, L. H. +2 more
We here present the luminosity function (LF) of globular clusters (GCs) in five nearby spiral galaxies using the samples of GC candidates selected in Hubble Space Telescope mosaic images in F435W, F555W, and F814W filters. Our search, which surpasses the fractional area covered by all previous searches in these galaxies, has resulted in the detect…
Superresolution trends in the ALMA Taurus survey: structured inner discs and compact discs
Tazzari, Marco; Rosotti, Giovanni P.; Clarke, Cathie J. +2 more
The 1.33-mm survey of protoplanetary discs in the Taurus molecular cloud found annular gaps and rings to be common in extended sources (≳ 55AU), when their 1D visibility distributions were fit parametrically. We first demonstrate the advantages and limitations of non-parametric visibility fits for data at the survey's 0.12-arcsec resolution. Then …
Modeling the kinematics of globular cluster systems
Chen, Yingtian; Gnedin, Oleg Y.
Globular clusters (GCs) are old massive star clusters that serve as 'fossils' of galaxy formation. The advent of Gaia observatory has enabled detailed kinematics studies of the Galactic GCs and revolutionized our understanding of the connections between GC properties and galaxy assembly. However, lack of kinematic measurements of extragalactic GCs…
Found: a rapidly spinning white dwarf in LAMOST J024048.51+195226.9.
Dhillon, V. S.; Breedt, E.; Marsh, T. R. +9 more
We present optical photometry of the cataclysmic variable LAMOST J024048.51+195226.9 taken with the high-speed, five-band CCD camera HiPERCAM on the 10.4 m Gran Telescopio Canarias (GTC). We detect pulsations originating from the spin of its white dwarf, finding a spin period of 24.9328(38)s. The pulse amplitude is of the order of 0.2% in the g-ba…
Helium absorption in exoplanet atmospheres is connected to stellar coronal abundances
Poppenhaeger, K.
Transit observations in the helium triplet around 10 830 Angstrom are a successful tool to study exoplanetary atmospheres and their mass loss. Forming those lines requires ionization and recombination of helium in the exoplanetary atmosphere. This ionization is caused by stellar photons at extreme ultraviolet (EUV) wavelengths; however, no current…
Spectral analysis of ultra-cool white dwarfs polluted by planetary debris
Gänsicke, Boris T.; Gentile Fusillo, Nicola Pietro; Koester, Detlev +5 more
We identify two ultra-cool (${T_\mathrm{eff}}\lt 4000$ K) metal-polluted (DZ) white dwarfs WD J2147-4035 and WD J1922+0233 as the coolest and second coolest DZ stars known to date with ${T_\mathrm{eff}}\approx 3050$ K and ${T_\mathrm{eff}}\approx 3340$ K, respectively. Strong atmospheric collision-induced absorption (CIA) causes the suppression of…