Search Publications
Probing UV-sensitive Pathways for CN and HCN Formation in Protoplanetary Disks with the Hubble Space Telescope
France, Kevin; Hoadley, Keri; Manara, Carlo F. +6 more
The UV radiation field is a critical regulator of gas-phase chemistry in surface layers of disks around young stars. In an effort to understand the relationship between photocatalyzing UV radiation fields and gas emission observed at infrared and submillimeter wavelengths, we present an analysis of new and archival Hubble Space Telescope (HST), Sp…
Forward modelling the multiwavelength properties of active galactic nuclei: application to X-ray and WISE mid-infrared samples
Ruiz, Angel; Georgakakis, Antonis; LaMassa, Stephanie M.
An empirical forward-modelling framework is developed to interpret the multiwavelength properties of active galactic nuclei (AGNs) and provide insights into the overlap and incompleteness of samples selected at different parts of the electromagnetic spectrum. The core of the model are observationally derived probabilites on the occupation of galax…
The braking index of PSR B0540-69 and the associated pulsar wind nebula emission after spin-down rate transition
Zhang, S. N.; Dai, Z. G.; Ge, M. Y. +6 more
In 2011 December, PSR B054-69 experienced a spin-down rate transition (SRT), after which the spin-down power of the pulsar increased by $\sim 36{{\ \rm per\ cent}}$. About 1000 d after the SRT, the X-ray luminosity of the associated pulsar wind nebula (PWN) was found to brighten by $32\pm 8{{\ \rm per\ cent}}$. After the SRT, the braking index n o…
Persistent Emission Properties of SGR J1935+2154 during Its 2020 Active Episode
Göğüş, Ersin; Kouveliotou, Chryssa; Lin, Lin +6 more
We present detailed spectral and temporal characteristics of the persistent X-ray emission of SGR J1935+2154 based on our XMM-Newton and Chandra observations taken in the aftermath of its 2020 April burst storm, during which hundreds of energetic X-ray bursts were emitted, including one associated with an extraordinary fast radio burst. We clearly…
The nature of the photometric variability of HgMn stars: a test of simulated light curves of φ Phe against the TESS data
Krtička, Jiří; Korhonen, Heidi; Prvák, Milan
The inhomogeneous surface distribution of heavy elements is known to cause periodic light variability of magnetic chemically peculiar stars. It is unclear to what extent the same paradigm applies to mercury-manganese (HgMn) stars. We aim to model the photometric variability of the HgMn star φ Phe using abundance maps obtained from high-resolution …
Herschel/PACS OH Spectroscopy of Seyfert, LINER, and Starburst Galaxies
Spinoglio, Luigi; Fernández-Ontiveros, Juan Antonio; Malkan, Matthew A. +2 more
We investigated the 65, 71, 79, 84, 119, and 163 µm OH doublets of 178 local (0 < z < 0.35) galaxies. They were observed using the Herschel/Photoconductor Array Camera and Spectrometer, including Seyfert galaxies, low-ionization nuclear emission-line regions, and star-forming galaxies. We observe these doublets exclusively in absorptio…
The MESAS Project: ALMA Observations of the F-type Stars γ Lep, γ Vir A, and γ Vir B
De la Luz, V.; Moór, A.; White, Jacob Aaron +7 more
The spectrum of stars in the submillimeter to centimeter wavelength range remains poorly constrained due to a lack of data for most spectral types. An accurate characterization of stellar emission in this regime is needed to test stellar atmosphere models, and is also essential for revealing emission associated with unresolved circumstellar debris…
Searching for globular cluster chemical anomalies on the main sequence of a young massive cluster
Martocchia, S.; Dalessandro, E.; Salaris, M. +9 more
The spectroscopic and photometric signals of the star-to-star abundance variations found in globular clusters seem to be correlated with global parameters like the cluster's metallicity, mass, and age. Understanding this behaviour could bring us closer to the origin of these intriguing abundance spreads. In this work we use deep HST photometry to …
Mathematical Underpinnings of the Multiwavelength Structure of the Tip of the Red Giant Branch
Madore, Barry F.; Freedman, Wendy L.
We consider the application of the tip of the red giant branch (TRGB) in the optical and in the near-infrared for the determination of distances to nearby galaxies. We analyze ACS VI (F555W and F814W) data and self-consistently cross-calibrate WFC3-IR JH (F110W and F120W) data using an absolute magnitude calibration of MI = -4.05 mag as…
New Candidates for Planetary-mass Brown Dwarfs in IC 348
Luhman, K. L.; Hapich, C. J.
We have used infrared images obtained with the Wide Field Camera 3 on board the Hubble Space Telescope to search for planetary-mass brown dwarfs in the star-forming cluster IC 348. In those images, we have identified 12 objects that have colors indicative of spectral types later than M8, corresponding to masses of ≲30 MJup at the age of…