Search Publications
The “UV-route” to Search for Blue Straggler Stars in Globular Clusters: First Results from the HST UV Legacy Survey
Dalessandro, E.; Nardiello, D.; Vesperini, E. +4 more
We used data from the Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters to select the Blue Straggler Star (BSS) population in four intermediate/high density systems (namely NGC 2808, NGC 6388, NGC 6541, and NGC 7078) through a “UV-guided search.” This procedure consists of using the F275W images in each cluster to construct the…
Importance of CME Radial Expansion on the Ability of Slow CMEs to Drive Shocks
Lugaz, Noé; Farrugia, Charles J.; Winslow, Reka M. +3 more
Coronal mass ejections (CMEs) may disturb the solar wind by overtaking it or expanding into it, or both. CMEs whose front moves faster in the solar wind frame than the fast magnetosonic speed drive shocks. Such shocks are important contributors to space weather, by triggering substorms, compressing the magnetosphere, and accelerating particles. In…
Exploring the Inner Acceleration Region of Solar Wind: A Study Based on Coronagraphic UV and Visible Light Data
Bemporad, A.
This work combined coronagraphic visible light (VL) and UV data to provide with an unprecedented view of the inner corona where the nascent solar wind is accelerated. The UV (H I Lyα) and VL (polarized brightness) images (reconstructed with SOHO/UVCS, LASCO, and Mauna Loa data) have been analyzed with the Doppler dimming technique to provide for t…
Specific Frequencies and Luminosity Profiles of Cluster Galaxies and Intracluster Light in Abell 1689
Blakeslee, J. P.; Alamo-Martínez, K. A.
We present magnitudes and profile fits for 180 galaxies in the central field of the massive lensing cluster Abell 1689 using very deep imaging with the Hubble Space Telescope Advanced Camera for Surveys in the F814W bandpass. Previous work revealed an exceptionally large number of globular clusters (GCs) in A1689 and mapped their number density di…
Photometric Determination of the Mass Accretion Rates of Pre-main-sequence Stars. V. Recent Star Formation in the 30 Dor Nebula
Panagia, Nino; Beccari, Giacomo; De Marchi, Guido
We report on the properties of the low-mass stars that recently formed in the central ∼ 2\buildrel{ \prime}\over{.} 7× 2\buildrel{ \prime}\over{.} 7 of 30 Dor, including the R136 cluster. Using the photometric catalog of De Marchi et al., based on observations with the Hubble Space Telescope, and the most recent extinction law for this field, we i…
Shedding Light on the Compton-thick Active Galactic Nucleus in the Ultraluminous Infrared Galaxy UGC 5101 with Broadband X-Ray Spectroscopy
Imanishi, Masatoshi; Tanimoto, Atsushi; Ueda, Yoshihiro +3 more
We report the broadband X-ray spectra of the ultraluminous infrared galaxy (ULIRG) UGC 5101 in the 0.25-100 keV band observed with the Swift/Burst Alert Telescope (BAT), Nuclear Spectroscopic Telescope Array (NuSTAR), Suzaku, XMM-Newton, and Chandra. A Compton-thick active galactic nucleus (AGN) obscured with a hydrogen column density of ≈ 1.3× {1…
Lyα and UV Sizes of Green Pea Galaxies
Leitherer, Claus; Wofford, Aida; Malhotra, Sangeeta +4 more
Green Peas are nearby analogs of high-redshift Lyα-emitting galaxies (LAEs). To probe their Lyα escape, we study the spatial profiles of Lyα and UV continuum emission of 24 Green Pea galaxies using the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope. We extract the spatial profiles of Lyα emission from their 2D COS spectra, and of …
The Rotation-Activity Correlations in K and M Dwarfs. II. New Constraints on the Dynamo Mechanisms in Late-K and M Dwarfs Before and At the Transition to Complete Convection
Mullan, D. J.; Gebran, M.; Houdebine, E. R. +2 more
We study the rotation-activity correlations (RACs) in a sample of stars from spectral type dK4 to dM4. We study RACs using chromospheric data and coronal data. We study the Ca II line surface fluxes-P/\sin I RACs. We fit the RACs with linear homoscedastic and heteroscedastic regression models. We find that these RACs differ substantially from one …
A Hubble Space Telescope Survey for Novae in M87. II. Snuffing out the Maximum Magnitude-Rate of Decline Relation for Novae as a Non-standard Candle, and a Prediction of the Existence of Ultrafast Novae
Welch, D. L.; Lauer, Tod R.; Mikołajewska, Joanna +9 more
The extensive grid of numerical simulations of nova eruptions from the work of Yaron et al. first predicted that some classical novae might significantly deviate from the Maximum Magnitude-Rate of Decline (MMRD) relation, which purports to characterize novae as standard candles. Kasliwal et al. have announced the observational detection of a new c…
Investigating the Origins of Two Extreme Solar Particle Events: Proton Source Profile and Associated Electromagnetic Emissions
Vainio, Rami; Valtonen, Eino; Pohjolainen, Silja +13 more
We analyze the high-energy particle emission from the Sun in two extreme solar particle events in which protons are accelerated to relativistic energies and can cause a significant signal even in the ground-based particle detectors. Analysis of a relativistic proton event is based on modeling of the particle transport and interaction, from a near-…