Search Publications

First Detection of Sign-reversed Linear Polarization from the Forbidden [O I] 630.03 nm Line

de Wijn, A. G.; Socas-Navarro, H.; Vitas, N.

We report on the detection of linear polarization of the forbidden [O I] 630.03 nm spectral line. The observations were carried out in the broader context of the determination of the solar oxygen abundance, an important problem in astrophysics that still remains unresolved. We obtained spectro-polarimetric data of the forbidden [O I] line at 630.0…

Halo Pressure Profile through the Skew Cross-power Spectrum of the Sunyaev-Zel’dovich Effect and CMB Lensing in Planck

Cooray, Asantha; Feng, Chang; Keating, Brian +1 more

We measure the cosmic microwave background (CMB) skewness power spectrum in Planck, using frequency maps of the HFI instrument and the Sunyaev-Zel’dovich (SZ) component map. The two-to-one skewness power spectrum measures the cross-correlation between CMB lensing and the thermal SZ effect. We also directly measure the same cross-correlation using …

Radial Variations of Outward and Inward Alfvénic Fluctuations Based on Ulysses Observations

Wu, D. J.; Yang, L.; Shi, J. K. +4 more

Ulysses magnetic and plasma data are used to study hourly scale Alfvénic fluctuations in the solar polar wind. The calculated energy ratio {R}_{vA}²(cal) of inward to outward Alfvén waves is obtained from the observed Walén slope through an analytical expression, and the observed {R}_{vA}^2<…

Accurate Orbital Solution for the New and Metal-poor Eclipsing Binary Tycho 5227-1023-1

Munari, U.; Zwitter, T.; Traven, G. +1 more

The orbit and physical parameters of the previously unsolved double-lined eclipsing binary Tyc 5227-1023-1, discovered during the search for RR Lyr variable candidate members of the Aquarius stream, are derived using high-resolution échelle spectroscopy and V,{I}^\prime photometry. A synthetic spectral analysis of both components has be…

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; …