The Antennae galaxy (NGC 4038/39) is the closest major interacting galaxy system and is therefore often studied as a merger prototype. We present the first comprehensive integral field spectroscopic dataset of this system, observed with the MUSE instrument at the ESO VLT. We cover the two regions in this system which exhibit recent star formation: the central galaxy interaction and a region near the tip of the southern tidal tail. In these fields, we detect HII regions and diffuse ionized gas to unprecedented depth. About 15% of the ionized gas was undetected by previous observing campaigns. This newly detected faint ionized gas is visible everywhere around the central merger, and shows filamentary structure. We estimate diffuse gas fractions of about 60% in the central field and 10% in the southern region. We are able to show that the southern region contains a significantly different population of HII regions, showing fainter luminosities. By comparing HII region luminosities with the HST catalog of young star clusters in the central field, we estimate that there is enough Lyman-continuum leakage in the merger to explain the amount of diffuse ionized gas that we detect. We compare the Lyman-continuum escape fraction of each HII region against emission line ratios that are sensitive to the ionization parameter. While we find no systematic trend between these properties, the most extreme line ratios seem to be strong indicators of density bounded ionization. Extrapolating the Lyman-continuum escape fractions to the southern region, we conclude that simply from the comparison of the young stellar populations to the ionized gas there is no need to invoke other ionization mechanisms than Lyman-continuum leaking HII regions for the diffuse ionized gas in the Antennae.
We present an all-sky catalog of diffuse OVII and OVIII line intensities, extracted from archival XMM-Newton observations. This catalog supersedes our previous catalog (Henley et al., 2010, Cat. J/ApJS/187/388), which covered the sky between l=120{deg} and l=240{deg}. We attempted to reduce the contamination from near-Earth solar wind charge exchange (SWCX) emission by excluding times of high solar wind proton flux from the data. Without this filtering, we were able to extract measurements from 1868 observations. With this filtering, nearly half of the observations became unusable, and only 1003 observations yielded measurements. The OVII and OVIII intensities are typically ~2-11 and <~3 photons/cm^2^/s/sr (line unit, L.U.), respectively, although much brighter intensities were also recorded. Our data set includes 217 directions that have been observed multiple times by XMM-Newton. The time variation of the intensities from such directions may be used to constrain SWCX models.
The First Byurakan Survey (FBS) is the largest and the first systematic objective prism survey of the extragalactic sky. It covers 17,000 sq.deg. in the Northern sky together with a high galactic latitudes region in the Southern sky. The FBS has been carried out by B.E. Markarian, V.A. Lipovetski and J.A. Stepanian in 1965-1980 with the Byurakan Observatory 102/132/213 cm (40"/52"/84") Schmidt telescope using 1.5 deg. prism. Each FBS plate contains low-dispersion spectra of some 15,000-20,000 objects; the whole survey consists of about 20,000,000 objects.
Digitized First Byurakan Survey (DFBS) Extracted Spectra
Date:
06 Dec 2018 16:23:36
Publisher:
Byurakan Astrophysical Observatory
Description:
Raw metadata for the spectra, to be combined with image metadata like
date_obs and friends for a complete spectrum descriptions. This also
contains spectral and flux points in array-valued columns.
Digitized First Byurakan Survey (DFBS) Spectra Query Service
Short Name:
DFBS SSAP
Date:
24 Aug 2020 16:45:07
Publisher:
The staff at the ArVO Data Center
Description:
The First Byurakan Survey (FBS) is the largest and the first systematic
objective prism survey of the extragalactic sky. It covers 17,000 sq.deg.
in the Northern sky together with a high galactic latitudes region in the
Southern sky. The FBS has been carried out by B.E. Markarian, V.A.
Lipovetski and J.A. Stepanian in 1965-1980 with the Byurakan Observatory
102/132/213 cm (40"/52"/84") Schmidt telescope using 1.5 deg. prism. Each
FBS plate contains low-dispersion spectra of some 15,000-20,000 objects;
the whole survey consists of about 20,000,000 objects.
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