Search Publications
Metal-poor stars observed with the Magellan Telescope - IV. Neutron-capture element signatures in 27 main-sequence stars
Frebel, Anna; Mardini, Mohammad K.; Christlieb, Norbert +3 more
We present a chemo-dynamical analysis for 27 near main-sequence turnoff metal-poor stars, including 20 stars analysed for the first time. The sample spans a range in [Fe/H] from -2.5 to -3.6, with 44 per cent having [Fe/H]<-2.9. We derived chemical abundances for 17 elements, including strontium and barium. We derive Li abundances for the sampl…
JWST reveals star formation across a spiral arm in M33
Williams, Benjamin F.; Sandstrom, Karin M.; Johnson, L. Clifton +13 more
Young stellar objects (YSOs) are the gold standard for tracing star formation in galaxies but have been unobservable beyond the Milky Way and Magellanic Clouds. But that all changed when the JWST was launched, which we use to identify YSOs in the Local Group galaxy M33, marking the first time that individual YSOs have been identified at these larg…
The first white dwarf debris disc observed by JWST
Desch, Steven J.; Su, Kate Y. L.; Farihi, Jay +1 more
This letter reports the first JWST spectroscopy of a white dwarf debris disc, giving a preliminary assessment of the salient features, and recommendations for future observations. The polluted and dusty star WD 0145+234 experienced a major collisional event in its circumstellar disc in 2018, accompanied by an infrared outburst, and subsequently a …
Constraints on the narrow-line region of the X-ray quasi-periodic eruption source GSN 069
Filippenko, Alexei V.; Chiaberge, Marco; Miniutti, Giovanni +5 more
The origins of quasi-periodic eruptions (QPEs) are poorly understood, although most theoretical explanations invoke an accretion disc around a supermassive black hole. The gas and stellar environments in the galactic nuclei of these sources are also poorly constrained. In this paper, we present an analysis of archival Hubble Space Telescope (HST) …
Extending the chemical reach of the H3 survey: detailed abundances of the dwarf-galaxy stellar stream Wukong/LMS-1
Conroy, Charlie; Ting, Yuan-Sen; Naidu, Rohan P. +10 more
We present the first detailed chemical-abundance analysis of stars from the dwarf-galaxy stellar stream Wukong/LMS-1 covering a wide metallicity range ($-3.5 \lt \rm [Fe/H] \lesssim -1.3$). We find abundance patterns that are effectively indistinguishable from the bulk of Indus and Jhelum, a pair of smaller stellar streams proposed to be dynamical…
The MeerKAT 1.3 GHz Survey of the Small Magellanic Cloud
Haberl, F.; Filipović, M. D.; Indebetouw, R. +22 more
We present new radio continuum images and a source catalogue from the MeerKAT survey in the direction of the Small Magellanic Cloud. The observations, at a central frequency of 1.3 GHz across a bandwidth of 0.8 GHz, encompass a field of view ~7° × 7° and result in images with resolution of 8 arcsec. The median broad-band Stokes I image Root Mean S…
Repeating nuclear transients as candidate electromagnetic counterparts of LISA extreme mass ratio inspirals
Pasham, Dheeraj R.; Zajaček, Michal; Witzany, Vojtěch +2 more
Extreme mass ratio inspirals (EMRIs) are one of the primary targets for the recently adopted millihertz gravitational-wave observatory LISA. Some previous studies have argued that a fraction of all EMRIs form in matter-rich environments, and can potentially explain the dozens of soft X-ray band ($\sim 10^{-1}\,\rm keV$), low-frequency ($\sim 0.1$ …
Narrow-line Seyfert 1 galaxies in Sloan Digital Sky Survey: a new optical spectroscopic catalogue
Stalin, C. S.; Saikia, D. J.; Domínguez, Alberto +1 more
Narrow-line Seyfert 1 (NLSy1) galaxies are an enigmatic class of active galactic nuclei (AGN) that exhibit peculiar multiwavelength properties across the electromagnetic spectrum. For example, these sources have allowed us to explore the innermost regions of the central engine of AGN using X-ray observations and have also provided clues about the …
Galactic 'Snake' IRDC G11.11-0.12: a site of multiple hub-filament systems and colliding filamentary clouds
Dewangan, L. K.; Sharma, Saurabh; Eswaraiah, C. +3 more
To probe star formation processes, we present a multiscale and multiwavelength investigation of the 'Snake' nebula/infrared dark cloud G11.11-0.12 (hereafter, G11; length ~27 pc). Spitzer images hint at the presence of subfilaments (in absorption), and reveal four infrared-dark hub-filament system (HFS) candidates (extent < 6 pc) towards G11, w…
New insights into the role of AGNs in forming the cluster red sequence
Koyama, Yusei; Kodama, Tadayuki; Shimakawa, Rhythm +7 more
As a considerable investment of time from various telescope facilities was dedicated toward studying the Spiderweb protocluster at z = 2.2, it so far remains one of the most extensively studied protocluster. We report here the latest results in this field, adding a new dimension to previous research on cluster formation at high redshift. Previous …