Search Publications

Erratum: “On the Existence of the Kolmogorov Inertial Range in the Terrestrial Magnetosheath Turbulence” (2017, ApJL, 836, L10)

Sahraoui, F.; Deng, X. H.; Huang, S. Y. +2 more

Optical, Near-IR, and X-Ray Observations of SN 2015J and Its Host Galaxy

Boutsia, K.; Testa, V.; Nucita, A. A. +7 more

SN 2015J was discovered on 2015 April 27th and is classified as an SN IIn. At first, it appeared to be an orphan SN candidate, I.e., without any clear identification of its host galaxy. Here, we present an analysis of the observations carried out by the VLT 8 m class telescope with the FORS2 camera in the R band and the Magellan telescope (6.5 m) …

A Simple Pile-up Model for Time Series Analysis

Sevilla, Diego J. R.

In this paper, a simple pile-up model is presented. This model calculates the probability P(n| N) of having n counts if N particles collide with a sensor during an exposure time. Through some approximations, an analytic expression depending on only one parameter is obtained. This parameter characterizes the pile-up magnitude, and depends on featur…

PHL 6625: A Minor Merger-associated QSO Behind NGC 247

Tao, Lian; Feng, Hua; Kaaret, Philip +5 more

PHL 6625 is a luminous quasi-stellar object (QSO) at z = 0.3954 located behind the nearby galaxy NGC 247 (z = 0.0005). Hubble Space Telescope observations revealed an arc structure associated with it. We report on spectroscopic observations with the Very Large Telescope and multiwavelength observations from the radio to the X-ray band for the syst…

Transient X-Ray Sources in the Magellanic-type Galaxy NGC 4449

Jithesh, V.; Wang, Zhongxiang

We report the identification of seven transient X-ray sources in the nearby Magellanic-type galaxy NGC 4449 using archival multi-epoch X-ray observations conducted with the Chandra, XMM-Newton, and Swift telescopes over the years 2001-2013. Among them, two sources are classified as supersoft X-ray sources (SSSs) because of their soft X-ray color; …

Mesa Isochrones and Stellar Tracks (MIST). I. Solar-scaled Models

Choi, Jieun; Conroy, Charlie; Dotter, Aaron +3 more

This is the first of a series of papers presenting the Modules for Experiments in Stellar Astrophysics (MESA) Isochrones and Stellar Tracks (MIST) project, a new comprehensive set of stellar evolutionary tracks and isochrones computed using MESA, a state-of-the-art open-source 1D stellar evolution package. In this work, we present models with sola…

A 2.4% Determination of the Local Value of the Hubble Constant

Casertano, Stefano; Filippenko, Alexei V.; Foley, Ryan J. +12 more

We use the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope (HST) to reduce the uncertainty in the local value of the Hubble constant from 3.3% to 2.4%. The bulk of this improvement comes from new near-infrared (NIR) observations of Cepheid variables in 11 host galaxies of recent type Ia supernovae (SNe Ia), more than doubling the sample o…

A Remarkably Luminous Galaxy at z=11.1 Measured with Hubble Space Telescope Grism Spectroscopy

Brammer, G.; Trenti, M.; Oesch, P. A. +15 more

We present Hubble WFC3/IR slitless grism spectra of a remarkably bright z ≳ 10 galaxy candidate, GN-z11, identified initially from CANDELS/GOODS-N imaging data. A significant spectroscopic continuum break is detected at λ =1.47+/- 0.01 µ {{m}}. The new grism data, combined with the photometric data, rule out all plausible lower redshift solu…

Fermi GBM Observations of LIGO Gravitational-wave Event GW150914

McBreen, S.; Meegan, C. A.; McEnery, J. E. +32 more

With an instantaneous view of 70% of the sky, the Fermi Gamma-ray Burst Monitor (GBM) is an excellent partner in the search for electromagnetic counterparts to gravitational-wave (GW) events. GBM observations at the time of the Laser Interferometer Gravitational-wave Observatory (LIGO) event GW150914 reveal the presence of a weak transient above 5…

Discovery of Coherent Pulsations from the Ultraluminous X-Ray Source NGC 7793 P13

Harrison, F. A.; Ptak, A.; Stern, D. +12 more

We report the detection of coherent pulsations from the ultraluminous X-ray source (ULX) NGC 7793 P13. The ≈0.42 s nearly sinusoidal pulsations were initially discovered in broadband X-ray observations using XMM-Newton and NuSTAR taken in 2016. We subsequently also found pulsations in archival XMM-Newton data taken in 2013 and 2014. The significan…