Search Publications
Empirical Bolometric Fluxes and Angular Diameters of 1.6 Million Tycho-2 Stars and Radii of 350,000 Stars with Gaia DR1 Parallaxes
Stassun, Keivan G.; Stevens, Daniel J.; Gaudi, B. Scott
We present bolometric fluxes and angular diameters for over 1.6 million stars in the Tycho-2 catalog, determined using previously determined empirical color-temperature and color-flux relations. We vet these relations via full fits to the full broadband spectral energy distributions for a subset of benchmark stars and perform quality checks agains…
Observations of the Formation, Development, and Structure of a Current Sheet in an Eruptive Solar Flare
Seaton, Daniel B.; Bartz, Allison E.; Darnel, Jonathan M.
We present Atmospheric Imaging Assembly observations of a structure we interpret as a current sheet associated with an X4.9 flare and coronal mass ejection that occurred on 2014 February 25 in NOAA Active Region 11990. We characterize the properties of the current sheet, finding that the sheet remains on the order of a few thousand kilometers thic…
The MUSE Hubble Ultra Deep Field Survey. VII. Fe II* emission in star-forming galaxies
Feltre, Anna; Bacon, Roland; Finley, Hayley +15 more
Non-resonant Fe II* (λ2365, λ2396, λ2612, λ2626) emission can potentially trace galactic winds in emission and provide useful constraints to wind models. From the 3.15' × 3.15' mosaic of the Hubble Ultra Deep Field (UDF) obtained with the VLT/MUSE integral field spectrograph, we identify a statistical sample of 40 Fe II* emitters and 50 Mg II (λλ2…
CHEERS Results from NGC 3393. II. Investigating the Extended Narrow-line Region Using Deep Chandra Observations and Hubble Space Telescope Narrow-line Imaging
Elvis, Martin; Raymond, John; Storchi-Bergmann, Thaisa +5 more
The CHandra Extended Emission Line Region Survey (CHEERS) is an X-ray study of nearby active galactic nuclei (AGNs) designed to take full advantage of Chandra's unique angular resolution by spatially resolving feedback signatures and effects. In the second paper of a series on CHEERS target NGC 3393, we examine deep high-resolution Chandra images …
Planck's dusty GEMS. IV. Star formation and feedback in a maximum starburst at z = 3 seen at 60-pc resolution
Kneissl, R.; Le Floc'h, E.; Scott, D. +7 more
We present an analysis of high-resolution ALMA interferometry of CO(4-3) line emission and dust continuum in the "Ruby" (PLCK_G244.8+54.9), a bright, gravitationally lensed galaxy at z = 3.0 discovered with the Planck all-sky survey. The Ruby is the brightest of Planck's dusty GEMS, a sample of 11 of the brightest gravitationally lensed high-redsh…
Identification of Low Coronal Sources of “Stealth” Coronal Mass Ejections Using New Image Processing Techniques
Morgan, Huw; Alzate, Nathalia
Coronal mass ejections (CMEs) are generally associated with low coronal signatures (LCSs), such as flares, filament eruptions, extreme ultraviolet (EUV) waves, or jets. A number of recent studies have reported the existence of stealth CMEs as events without LCSs, possibly due to observational limitations. Our study focuses on a set of 40 stealth C…
IRIS, Hinode, SDO, and RHESSI Observations of a White Light Flare Produced Directly by Nonthermal Electrons
Lee, Kyoung-Sun; Brooks, David H.; Watanabe, Kyoko +2 more
An X1.6 flare occurred in active region AR 12192 on 2014 October 22 at 14:02 UT and was observed by Hinode, IRIS, SDO, and RHESSI. We analyze a bright kernel that produces a white light (WL) flare with continuum enhancement and a hard X-ray (HXR) peak. Taking advantage of the spectroscopic observations of IRIS and Hinode/EIS, we measure the tempor…
Gaia's view of the λ Boo star puzzle
Murphy, Simon J.; Paunzen, Ernst
The evolutionary status of the chemically peculiar class of λ Boo stars has been intensely debated. It is now agreed that the λ Boo phenomenon affects A stars of all ages, from star formation to the terminal age main sequence, but the cause of the chemical peculiarity is still a puzzle. We revisit the debate of their ages and temperatures in order…
Narrowing down the possible explanations of cosmic acceleration with geometric probes
Dhawan, Suhail; Goobar, Ariel; Mörtsell, Edvard +2 more
Recent re-calibration of the Type Ia supernova (SNe Ia) magnitude-redshift relation combined with cosmic microwave background (CMB) and baryon acoustic oscillation (BAO) data have provided excellent constraints on the standard cosmological model. Here, we examine particular classes of alternative cosmologies, motivated by various physical mechanis…
Thermonuclear Burst Observations for Model Comparisons: A Reference Sample
Galloway, Duncan K.; Goodwin, Adelle J.; Keek, Laurens
We present observations of thermonuclear (type-I) X-ray bursts, selected for comparison with numerical models. We provide examples of four distinct cases of ignition: He-ignition in mixed H/He fuel (case 1); He-ignition in pure He fuel, following exhaustion of accreted H by steady burning (case 2); ignition in (almost) pure He accumulated from an …