Search Publications

The surface mass density of the Milky Way: does the traditional K_Z approach work in the context of new surveys?

Majewski, Steven R.; Cheng, Xinlun; Anguiano, Borja +1 more

We revisit the classical K_Z problem - determination of the vertical force and implied total mass density distribution of the Milky Way disc - for a wide range of Galactocentric radius and vertical height using chemically selected thin and thick disc samples based on Apache Point Observatory Galactic Evolution Experiment spectroscopy com…

Study of the energetic X-ray superflares from the active fast rotator AB doradus

Srivastava, A. K.; Singh, Gurpreet; Pandey, Jeewan C. +1 more

We present the analyses of intense X-ray flares detected on the active fast rotator AB Dor using observations from the XMM-Newton. A total of 21 flares are detected, and 13 flares are analysed in detail. The total X-ray energy of these flares is found to be in the range of 10^34-36 erg, in which the peak flare flux increased up to 34 tim…

The properties of RR Lyrae variable stars in the Local Group dwarf galaxy LGS-3

Sarajedini, Ata

We present a sample of 56 RR Lyrae variable stars (48 ab-type and 8 c-type) measured from a set of F475W (≈B filter) and F814W (≈I filter) archival images taken with the Hubble Space Telescope/Advanced Camera for Surveys of one field in the Local Group dwarf galaxy LGS-3 (also known as the Pisces Dwarf or Pisces I). The ab-type variables exhibit a…

DEVILS/MIGHTEE/GAMA/DINGO: the impact of SFR time-scales on the SFR-radio luminosity correlation

Holwerda, Benne W.; Knowles, Kenda; Driver, Simon P. +20 more

The tight relationship between infrared luminosity (L_TIR) and 1.4 GHz radio continuum luminosity ($L_\mathrm{1.4\, GHz}$) has proven useful for understanding star formation free from dust obscuration. Infrared emission in star-forming galaxies typically arises from recently formed, dust-enshrouded stars, whereas radio synchrotron emissi…

Correction to: The cosmic dipole in the Quaia sample of quasars: a Bayesian analysis

Lewis, Geraint F.; Mittal, Vasudev; Oayda, Oliver T.

Proof of principle X-ray reflection mass measurement of the black hole in H1743-322

Ingram, Adam; Steiner, James F.; García, Javier A. +9 more

The black hole X-ray binary H1743-322 lies in a region of the Galaxy with high extinction, and therefore it has not been possible to make a dynamical mass measurement. In this paper, we make use of a recent model which uses the X-ray reflection spectrum to constrain the ratio of the black hole mass to the source distance. By folding in a reported …

Shedding far-ultraviolet light on the donor star and evolutionary state of the neutron-star LMXB Swift J1858.6-0814

Altamirano, D.; Degenaar, N.; Knigge, C. +13 more

The evolution of accreting X-ray binary systems is closely coupled to the properties of their donor stars. Consequently, we can constrain the evolutionary track a system is by establishing the nature of its donor. Here, we present far-ultraviolet (far-UV) spectroscopy of the transient neutron-star low-mass X-ray binary J1858 in different accretion…

Applying machine learning to Galactic Archaeology: how well can we recover the origin of stars in Milky Way-like galaxies?

McCarthy, Ian G.; Font, Andreea S.; Sante, Andrea +2 more

We present several machine learning (ML) models developed to efficiently separate stars formed in situ in Milky Way-type galaxies from those that were formed externally and later accreted. These models, which include examples from artificial neural networks, decision trees, and dimensionality reduction techniques, are trained on a sample of disc-l…

Dissecting the morphology of star forming complex S193

Ojha, D. K.; Pandey, Rakesh; Sharma, Saurabh +6 more

We have studied a star-forming complex S193 using near-infrared (NIR) observations and other archival data covering optical to radio wavelengths. We identified stellar clusters in the complex using the NIR photometric data and estimated the membership and distance of the clusters. Using the mid-infrared (MIR) and far-infrared (FIR) images, the dis…

Cold diffuse interstellar medium of Magellanic Clouds: II. Physical conditions from excitation of C I and H₂

Balashev, S. A.; Klimenko, V. V.; Kosenko, D. N.

We present a comprehensive study of the excitation of C I fine-structure levels along 57 sight lines in the Large and Small Magellanic Clouds (LMC and SMC). The sightlines were selected by the detection of H₂ in FUSE spectra. Using archival HST/COS and HST/STIS spectra, we detected absorption of C I fine-structure levels and measured th…