Search Publications
The star formation history in the M31 bulge
Olsen, Knut; Saha, Abhijit; Dong, Hui +4 more
We present the study of stellar populations in the central 5.5 arcmin (∼1.2 kpc) of the M31 bulge by using the optical colour magnitude diagram derived from the observations taken by HST Advanced Camera for Surveys observations. In order to enhance image quality and then obtain deeper photometry, we construct Nyquist-sampled images and use a decon…
The low-mass pre-main sequence population of Scorpius OB1
Damiani, Francesco
Context. The low-mass members of OB associations, expected to be a major component of their total population, are in most cases poorly studied because of the difficulty of selecting these faint stars in crowded sky regions. Our knowledge of many OB associations relies on only a relatively small number of massive members.
Aims: We study here t…
Solar Coronal Jets Extending to High Altitudes Observed during the 2017 August 21 Total Eclipse
Hanaoka, Yoichiro; Nakazawa, Jun; Ohgoe, Osamu +11 more
Coronal jets, which extend from the solar surface to beyond 2 R ⊙, were observed in the polar coronal hole regions during the total solar eclipse on 2017 August 21. In a time-series of white-light images of the corona spanning 70 minutes taken with our multi-site observations of this eclipse, six jets were found as narrow structures upw…
A Bayesian Framework for Exoplanet Direct Detection and Non-detection
De Rosa, Robert J.; Macintosh, Bruce; Nielsen, Eric L. +9 more
Rigorously quantifying the information in high-contrast imaging data is important for informing follow-up strategies to confirm the substellar nature of a point source, constraining theoretical models of planet-disk interactions, and deriving planet occurrence rates. However, within the exoplanet direct imaging community, non-detections have almos…
Deep ALMA photometry of distant X-ray AGN: improvements in star formation rate constraints, and AGN identification
Alexander, D. M.; Knudsen, K. K.; Rosario, D. J. +5 more
We present the star formation rates (SFRs) of a sample of 109 galaxies with X-ray-selected active galactic nuclei (AGNs) with moderate to high X-ray luminosities (L_2-8 keV = 10^{42}-10^{45} erg s^{-1}), at redshifts 1 < z < 4.7, that were selected to be faint or undetected in the Herschel bands. We combine our deep Atacama large (sub-)milli…
Probing a steep EoS for dark energy with latest observations
Jaber, Mariana; Macorra, Axel de la
We present a parametrization for the Dark Energy Equation of State "EoS" which has a rich structure, performing a transition at pivotal redshift zT between the present day value w0 to an early time wi =wa +w0 ≡ w(z ≫ 0) with a steepness given in terms of q parameter. The proposed parametrizati…
Constraining Type Ia Supernova Progenitor Scenarios with Extremely Late-time Photometry of Supernova SN 2013aa
Kilpatrick, Charles D.; Foley, Ryan J.; Jacobson-Galán, Wynn V. +1 more
We present Hubble Space Telescope observations and photometric measurements of the Type Ia supernova (SN Ia) SN 2013aa 1500 days after explosion. At this epoch, the luminosity is primarily dictated by the amounts of radioactive {}57{{Co}} and {}55{{Fe}}, while at earlier epochs, the luminosity depends on the amount of radioac…
Constraints on the Location of γ-Ray Sample of Blazars with Radio Core-shift Measurements
Chen, Liang; Wu, Qingwen; Wu, Linhui +2 more
We model simultaneous or quasi-simultaneous multi-band spectral energy distributions (SEDs) for a sample of 25 blazars that have radio core-shift measurements, where a one-zone leptonic model and Markov chain Monte Carlo technique are adopted. In the SED fitting for 23 low-synchrotron-peaked (LSP) blazars, the seed photons from the broad-line (BLR…
X-ray, UV, and optical observations of the accretion disk and boundary layer in the symbiotic star RT Crucis
Nuñez, N. E.; Nelson, T.; Mukai, K. +8 more
Compared to mass transfer in cataclysmic variables, the nature of accretion in symbiotic binaries in which red giants transfer material to white dwarfs (WDs) has been difficult to uncover. The accretion flows in a symbiotic binary are most clearly observable, however, when there is no quasi-steady shell burning on the WD to hide them. RT Cru is th…
Investigation of Energetic Particle Release Using Multi-point Imaging and In Situ Observations
Wang, Rui; Liu, Ying D.; Kwon, Ryun-Young +1 more
The solar eruption on 2012 January 27 resulted in a wide-spread solar energetic particle event observed by STEREO A and the near-Earth spacecraft (separated by 108°). The event was accompanied by an X-class flare, extreme-ultraviolet (EUV) wave and fast coronal mass ejection. We investigate the particle release by comparing the release times of pa…