Search Publications
Using Shell models to investigate clumping in the wind of the O7Iaf + supergiant AzV83
Hillier, D. John; Flores, Brian L.
Hot massive stars exhibit strong stellar winds that enrich the surrounding interstellar medium and affect the stars' evolution. However, the winds are inhomogeneous (clumped) and are difficult to model in radiative transfer codes. To produce more realistic spectra, many codes use a volume-filling factor (VFF) approach to incorporate the effects of…
AstroSat soft X-ray observations of the symbiotic recurrent nova V3890 Sgr during its 2019 outburst
Singh, K. P.; Orio, M.; Ness, Jan-Uwe +3 more
Two long AstroSat Soft X-ray Telescope observations were taken of the third recorded outburst of the symbiotic recurrent nova V3890 Sgr. The first observing run, 8.1-9.9 d after the outburst, initially showed a stable intensity level with a hard X-ray spectrum that we attribute to shocks between the nova ejecta and the pre-existing stellar compani…
The stratified disc wind of MCG-03-58-007
Ballo, L.; Reeves, J. N.; Braito, V. +6 more
Past Suzaku, XMM-Newton, and NuSTAR observations of the nearby (z = 0.03233) bright Seyfert 2 galaxy MCG-03-58-007 revealed the presence of two deep and blue-shifted iron K-shell absorption line profiles. These could be explained with the presence of two phases of a highly ionized, high column density accretion disc wind outflowing with vout1…
A massive open cluster hiding in full sight
Chené, A. -N.; Negueruela, I.; Tabernero, H. M. +4 more
Obscuration and confusion conspire to limit our knowledge of the inner Milky Way. Even at moderate distances, the identification of stellar systems becomes compounded by the extremely high density of background sources. Here, we provide a very revealing example of these complications by unveiling a large, massive, young cluster in the Sagittarius …
The precessing jets of classical nova YZ Reticuli
Blundell, Katherine M.; Lee, Steven; McLoughlin, Dominic +1 more
The classical nova YZ Reticuli was discovered in 2020 July. Shortly after this, we commenced a sustained, highly time-sampled coverage of its subsequent rapid evolution with time-resolved spectroscopy from the Global Jet Watch observatories. Its H-alpha complex exhibited qualitatively different spectral signatures in the following weeks and months…
The mid-infrared Leavitt law for classical Cepheids in the Magellanic Clouds
Wuyts, Stijn; Scowcroft, Victoria; Chown, Abigail H.
The Cepheid Leavitt Law (LL), also known as the Period-Luminosity relation, is a crucial tool for assembling the cosmic distance ladder. By combining data from the OGLE-IV catalogue with mid-infrared photometry from the Spitzer Space Telescope, we have determined the 3.6 and 4.5 $\mu$m LLs for the Magellanic Clouds using ~5000 fundamental-mode cla…
2MASX J00423991 + 3017515: an offset active galactic nucleus in an interacting system
Reynolds, Christopher S.; Blecha, Laura; Smith, Krista Lynne +2 more
We present a spectroscopic and imaging study of an abnormal active galactic nucleus (AGN), 2MASX J00423991 + 3017515. This AGN is newly identified in the hard X-rays by the Swift BAT All-Sky survey and found in an edge-on disc galaxy interacting with a nearby companion. Here, we analyse the first optical spectra obtained for this system (taken in …
Probing the circumnuclear environment of NGC 1275 with high-resolution X-ray spectroscopy
Fabian, Andrew C.; Fukazawa, Yasushi; Veilleux, Sylvain +6 more
NGC 1275 is the brightest cluster galaxy (BCG) in the Perseus cluster and hosts the active galactic nucleus (AGN) that is heating the central 100 kpc of the intracluster medium atmosphere via a regulated feedback loop. Here, we use a deep (490 ks) Cycle-19 Chandra High-Energy Transmission Grating (HETG) observation of NGC 1275 to study the anatomy…
The formation history of the Milky Way disc with high-resolution cosmological simulations
Lattanzi, Mario G.; Re Fiorentin, Paola; Spagna, Alessandro +3 more
We analyse from an observational perspective the formation history and kinematics of a Milky Way-like galaxy from a high-resolution zoom-in cosmological simulation that we compare to those of our Galaxy as seen by Gaia DR2 to better understand the origin and evolution of the Galactic thin and thick discs. The cosmological simulation was carried ou…
Optically detected galaxy cluster candidates in the AKARI North Ecliptic Pole field based on photometric redshift from the Subaru Hyper Suprime-Cam
Hashimoto, Tetsuya; Goto, Tomotsugu; Kim, Seong Jin +23 more
Galaxy clusters provide an excellent probe in various research fields in astrophysics and cosmology. However, the number of galaxy clusters detected so far in the AKARI North Ecliptic Pole (NEP) field is limited. In this work, we provide galaxy cluster candidates in the AKARI NEP field with the minimum requisites based only on the coordinates and …