Search Publications
Structural Parameters and Possible Association of the Ultra-faint Dwarfs Pegasus III and Pisces II from Deep Hubble Space Telescope Photometry
Choi, Yumi; van der Marel, Roeland P.; Geha, Marla +17 more
We present deep Hubble Space Telescope (HST) photometry of the ultra-faint dwarf (UFD) galaxies Pegasus III (Peg III) and Pisces II (Psc II), two of the most distant satellites in the halo of the Milky Way (MW). We measure the structure of both galaxies, derive mass-to-light ratios with newly determined absolute magnitudes, and compare our finding…
Validation of a Wave Heated 3D MHD Coronal-wind Model using Polarized Brightness and EUV Observations
Pinto, Rui F.; Réville, Victor; Strugarek, Antoine +5 more
The physical properties responsible for the formation and evolution of the corona and heliosphere are still not completely understood. 3D MHD global modeling is a powerful tool to investigate all the possible candidate processes. To fully understand the role of each of them, we need a validation process where the output from the simulations is qua…
New Time-resolved, Multi-band Flares in the GJ 65 System with gPhoton
Brasseur, C. E.; Osten, Rachel A.; Fleming, Scott W. +2 more
Characterizing the distribution of flare properties and occurrence rates is important for understanding habitability of M-dwarf exoplanets. The Galaxy Evolution Explorer (GALEX) space telescope observed the GJ 65 system, composed of the active, flaring M stars BL Cet and UV Cet, for 15,900 s (~4.4 hr) in two ultraviolet (UV) bands. The contrast in…
A Mass Model for the Lensing Cluster SDSS J1004+4112: Constraints from the Third Time Delay
Kochanek, C. S.; Muñoz, J. A.; Mediavilla, E. +1 more
We have built a new model for the lens system SDSS J1004+4112 including the recently measured time delay of the fourth quasar image. This time delay has a strong influence on the inner mass distribution of the lensing cluster (ρ ∝ r -α ) allowing us to determine $\alpha ={1.18}_{-0.03(-0.18)}^{+0.02(+0.11)}$ at the 68% (95%) confidence …
A Multiwavelength View of IC 860: What Is in Action inside Quenching Galaxies
Heckman, Timothy; Aalto, Susanne; French, K. Decker +15 more
We present a multiwavelength study of IC 860, a nearby post-starburst galaxy at the early stage of transitioning from blue and star forming to red and quiescent. Optical images reveal a galaxy-wide, dusty outflow originating from a compact core. We find evidence for a multiphase outflow in the molecular and neutral gas phase from the CO position-v…
Lyα Halos around [O III]-selected Galaxies in HETDEX
Finkelstein, Steven L.; Schneider, Donald P.; Gebhardt, Karl +13 more
We present extended Lyα emission out to 800 kpc of 1034 [O III]-selected galaxies at redshifts 1.9 < z < 2.35 using the Hobby-Eberly Telescope Dark Energy Experiment. The locations and redshifts of the galaxies are taken from the 3D-HST survey. The median-stacked surface brightness profile of the Lyα emission of the [O III]-selected galaxies…
The Donor of the Black Hole X-Ray Binary MAXI J1820+070
Mikołajewska, Joanna; Casares, Jorge; Zdziarski, Andrzej A. +2 more
We estimate the parameters of the donor of the accreting black hole binary MAXI J1820+070. The measured values of the binary period, rotational and radial velocities, and constraints on the orbital inclination imply the donor is a subgiant with the mass of ${M}_{2}\approx {0.49}_{-0.10}^{+0.10}{M}_{\odot }$ and the radius of ${R}_{2}\approx {1.19}…
Genesis and Coronal-jet-generating Eruption of a Solar Minifilament Captured by IRIS Slit-raster Spectra
Tiwari, Sanjiv K.; De Pontieu, Bart; Panesar, Navdeep K. +2 more
We present the first Mg II slit-raster spectra from the Interface Region Imaging Spectrograph (IRIS) that fully capture the genesis and coronal-jet-generating eruption of a central-disk solar minifilament. The minifilament arose in a negative-magnetic-polarity coronal hole. The Mg II spectroheliograms verify that the minifilament plasma temperatur…
Ultrafaint Dwarf Galaxy Candidates in the M81 Group: Signatures of Group Accretion
Bell, Eric F.; Monachesi, Antonela; Bailin, Jeremy +8 more
The faint and ultrafaint dwarf galaxies in the Local Group form the observational bedrock upon which our understanding of small-scale cosmology rests. In order to understand whether this insight generalizes, it is imperative to use resolved-star techniques to discover similarly faint satellites in nearby galaxy groups. We describe our search for u…
Constraints on Cosmological Parameters with a Sample of Type Ia Supernovae from JWST
Koekemoer, Anton M.; Baade, Dietrich; Wang, Lifan +7 more
We investigate the potential of using a sample of very high-redshift (2 ≲ z ≲ 6) (VHZ) Type Ia supernovae (SNe Ia) attainable by JWST on constraining cosmological parameters. At such high redshifts, the age of the universe is young enough that the VHZ SN Ia sample comprises the very first SNe Ia of the universe, with progenitors among the very fir…