Search Publications
Properties of F Stars with Stable Radial Velocity Timeseries: A Useful Metric for Selecting Low-jitter F Stars
Wright, Jason T.; Isaacson, Howard; Luhn, Jacob K.
In a companion paper, we have conducted an in-depth analysis of radial velocity jitter of over 600 stars, examining the astrophysical origins including stellar granulation, oscillation, and magnetic activity. In this paper, we highlight a subsample of those stars, specifically the main sequence and "retired" F stars -- which we refer to as "MSRF" …
A HaloSat Analysis of the Cygnus Superbubble
Kaaret, Philip; Kuntz, K. D.; Bluem, Jesse +5 more
The Cygnus Superbubble (CSB) is a region of soft X-ray emission approximately 13 degrees wide in the direction of the local spiral arm. Such a large region might be the result of strong stellar winds and supernovae from nearby stellar nurseries, or it could be the result of a single event—a hypernova. HaloSat observed four nonoverlapping 10 degree…
A Mystery in Chamaeleon: Serendipitous Discovery of a Galactic Symbiotic Nova
Ting, Yuan-Sen; Greene, Jenny E.; Pope, Benjamin J. S. +3 more
We present the serendipitous discovery of a low optical-luminosity nova occurring in a D-type symbiotic binary star system in the Milky Way. We lay out the extensive archival data alongside new follow-up observations related to the stellar object CN Cha in the constellation of Chamaeleon. The object had long period (250 days), high amplitude (3 ma…
Dust emission, extinction, and scattering in LDN 1642
Ysard, Nathalie; Juvela, Mika; Neha, Sharma +3 more
Context. LDN 1642 is a rare example of a star-forming, high-latitude molecular cloud. The dust emission of LDN 1642 has already been studied extensively in the past, but its location also makes it a good target for studies of light scattering.
Aims: We wish to study the near-infrared (NIR) light scattering in LDN 1642, its correlation with th…
On the Effects of UV Photons/X-Rays on the Chemistry of the Sgr B2 Cloud
Martín-Pintado, J.; Requena-Torres, M. A.; Llerena, M. +7 more
The lines of HOC+, HCO, and CO+ are considered good tracers of photon-dominated regions (PDRs) and X-ray-dominated regions. We study these tracers toward regions of the Sgr B2 cloud selected to be affected by different heating mechanisms. We find the lowest values of the column density ratios of HCO+ versus HOC
A Galactic dust devil: far-infrared observations of the Tornado supernova remnant candidate
De Looze, I.; Rho, J.; Dunne, L. +10 more
We present complicated dust structures within multiple regions of the candidate supernova remnant (SNR) the 'Tornado' (G357.7-0.1) using observations with Spitzer and Herschel. We use point process mapping, PPMAP, to investigate the distribution of dust in the Tornado at a resolution of 8 arcsec, compared to the native telescope beams of 5-36 arcs…
The complications of learning from Super Soft Source X-ray spectra
Ness, Jan-Uwe
Super Soft X-ray Sources (SSS) are powered by nuclear burning on the surface of an accreting white dwarf, they are seen around 0.1-1 keV (thus in the soft X-ray regime), depending on effective temperature and the amount of intervening interstellar neutral hydrogen (NH). The most realistic model to derive physical parameters from observe…
See Change: VLT spectroscopy of a sample of high-redshift Type Ia supernova host galaxies
Rubin, D.; Aldering, G.; Goobar, A. +10 more
The Supernova Cosmology Project has conducted the 'See Change' programme, aimed at discovering and observing high-redshift (1.13 ≤ z ≤ 1.75) Type Ia supernovae (SNe Ia). We used multifilter Hubble Space Telescope (HST) observations of massive galaxy clusters with sufficient cadence to make the observed SN Ia light curves suitable for a cosmologica…
A Beginner's Guide to Working with Astronomical Data
Pössel, Markus
This elementary review covers the basics of working with astronomical data, notably with images, spectra and higher-level (catalog) data. The basic concepts and tools are presented using both application software (DS9 and TOPCAT) and Python. The level of presentation is suitable for undergraduate students, but should also be accessible to advanced…
An extensive spectroscopic time series of three Wolf-Rayet stars - II. A search for wind asymmetries in the dust-forming WC7 binary WR137
Garrel, T.; Knapen, J. H.; Mauclaire, B. +39 more
We present the results of a 4-month, spectroscopic campaign of the Wolf-Rayet dust-making binary, WR137. We detect only small-amplitude random variability in the C III λ5696 emission line and its integrated quantities (radial velocity, equivalent width, skewness, and kurtosis) that can be explained by stochastic clumps in the wind of the WC star. …