Search Publications
The AstroSat UV deep field north: direct determination of the UV luminosity function and its evolution from z 0.8-0.4
Saha, Kanak; Mondal, Chayan; Bhattacharya, Souradeep
We characterize the evolution of the rest-frame 1500 Å UV luminosity function (UVLF) from AstroSat/UVIT F154W and N242W imaging in the Great Observatories Origins Survey North (GOODS-N) field. With deep FUV observations, we construct the UVLF for galaxies at z$\lt 0.13$ and subsequently characterize it with a Schechter function fit. The fitted par…
Isochrone fitting of the open cluster M67 in the era of Gaia and improved model physics
Stello, Dennis; Hon, Marc; Pinsonneault, Marc H. +3 more
The Gaia mission has provided highly accurate observations that have significantly reduced the scatter in the colour-magnitude diagrams of open clusters. As a result of the improved isochrone sequence of the open cluster M67, we have created new stellar models that avoid commonly used simplifications in 1D stellar modelling, such as mass-independe…
Infrared spectroscopy of SWIFT J0850.8-4219: identification of the second red supergiant X-ray binary in the Milky Way
Soria, Roberto; De, Kishalay; Daly, Fiona A.
High-mass X-ray binaries hosting red supergiant (RSG) donors are a rare but crucial phase in massive stellar evolution, with only one source previously known in the Milky Way. In this letter, we present the identification of the second Galactic RSG X-ray binary SWIFT J0850.8-4219. We identify the source 2MASS 08504008-4211514 as the likely infrare…
The GUAPOS project - V: The chemical ingredients of a massive stellar protocluster in the making
Testi, L.; Mininni, C.; Lorenzani, A. +9 more
Most stars, including the Sun, are born in rich stellar clusters containing massive stars. Therefore, the study of the chemical reservoir of massive star-forming regions is crucial to understand the basic chemical ingredients available at the dawn of planetary systems. We present a detailed study of the molecular inventory of the hot molecular cor…
Systematic comparison of neural networks used in discovering strong gravitational lenses
Sonnenfeld, Alessandro; Wong, Kenneth C.; Jaelani, Anton T. +6 more
Efficient algorithms are being developed to search for strong gravitational lens systems owing to increasing large imaging surveys. Neural networks have been successfully used to discover galaxy-scale lens systems in imaging surveys such as the Kilo Degree Survey, Hyper-Suprime Cam (HSC) Survey, and Dark Energy Survey over the last few years. Thus…
NGTS-28Ab: a short period transiting brown dwarf
Ramsay, Gavin; Jackman, James A. G.; Triaud, Amaury H. M. J. +43 more
We report the discovery of a brown dwarf orbiting a M1 host star. We first identified the brown dwarf within the Next Generation Transit Survey data, with supporting observations found in TESS sectors 11 and 38. We confirmed the discovery with follow-up photometry from the South African Astronomical Observatory, SPECULOOS-S, and TRAPPIST-S, and ra…
Polycyclic aromatic hydrocarbon emission in galaxies as seen with JWST
Rigopoulou, D.; Hunt, L. K.; Shimizu, T. +6 more
We present a systematic study of mid-infrared spectra of galaxies including star-forming galaxies and active galactic nuclei observed with JWST MIRI-MRS and NIRSpec-IFU. We focus on the relative variations of the 3.3, 6.2, 7.7, 11.3, 12.7, and 17 $\mu$m polycyclic aromatic hydrocarbon (PAH) features within spatially resolved regions of galaxies in…
Planetary Nebula NGC 2818: Revealing its complex 3D morphology
Boumis, P.; Chiotellis, A.; Derlopa, S. +3 more
We carry out an advanced morpho-kinematic analysis of the Planetary Nebula (PN) NGC 2818, whose complex morphology is described by a basic bipolar component, filamentary structures and a knotty central region. We performed an upgrated 3D Morpho-kinematic (MK) model by employing the SHAPE software, combining for the first time in PNe optical 2D spa…
Two successive EUV waves and a transverse oscillation of a quiescent prominence
Li, Y.; Yan, X. L.; Zhang, Q. M. +4 more
In this paper, we carry out multiwavelength observations of two successive extreme-ultraviolet (EUV) waves originating from active region (AR) NOAA 13575 and a transverse oscillation of a columnar quiescent prominence on 2024 February 9. A hot channel eruption generates an X3.4 class flare and the associated full-halo coronal mass ejection (CME), …
Star-formation activity of low-mass galaxies at the peak epoch of galaxy formation probed by deep narrow-band imaging
Suzuki, Tomoko L.; Koyama, Yusei; Kodama, Tadayuki +5 more
Low-mass galaxies at high redshifts are the building blocks of more massive galaxies at later times and are thus key populations for understanding galaxy formation and evolution. We have made deep narrow-band observations for two protoclusters and the general field in COSMOS at z ~ 2. In a clumpy young protocluster, USS1558-003, at z = 2.53, we fi…