Search

Start Over Subject spectroscopy Validation Level 2
1711. MUSE library of stellar spectra
ID:
ivo://CDS.VizieR/J/A+A/629/A100
Title:
MUSE library of stellar spectra
Short Name:
J/A+A/629/A100
Date:
21 Oct 2021
Publisher:
CDS
Description:
Empirical stellar spectral libraries have applications in both extragalactic and stellar studies, and they confer an advantage over theoretical libraries because they naturally include all relevant chemical species and physical processes. In recent years we have seen a stream of new sets of high-quality spectra, but increasing the spectral resolution and widening the wavelength coverage means resorting to multi-order echelle spectrographs. Assembling the spectra from many pieces results in lower fidelity of their shapes. We aim to offer the community a library of high-signal-to-noise spectra with reliable continuum shapes. Furthermore, the use of an integral field unit (IFU) alleviates the issue of slit losses. Our library was built with the MUSE (Multi-Unit Spectroscopic Explorer) IFU instrument. We obtained spectra over nearly the entire visual band ({lambda}~4800-9300{AA}). We assembled a library of 35 high-quality MUSE spectra for a subset of the stars from the X-shooter Spectral Library. We verified the continuum shape of these spectra with synthetic broadband colors derived from the spectra. We also report some spectral indices from the Lick system, derived from the new observations. We offer a high-fidelity set of stellar spectra covering the Hertzsprung-Russell diagram. These can be used for both extragalactic and stellar studies and demonstrate that the IFUs are excellent tools for building reliable spectral libraries.
1712. MUSE MATLAS-2019 spectral datacube
ID:
ivo://CDS.VizieR/J/A+A/640/A106
Title:
MUSE MATLAS-2019 spectral datacube
Short Name:
J/A+A/640/A106
Date:
21 Oct 2021
Publisher:
CDS
Description:
The MATLAS deep imaging survey has uncovered a plethora of dwarf galaxies in the low density environment it has mapped. A fraction of them are unusually extended and have a low-surface brightness. Among these so-called ultra-diffuse galaxies, a few seem to host an excess of globular clusters. With the integral-field unit spectrograph MUSE we have observed one of these galaxies - MATLAS J15052031+0148447 (MATLAS-2019) - located towards the nearby group NGC 5846 and measured its systemic velocity,age, and metallicity, and that of its globular clusters candidates. For the stellar body of MATLAS-2019 we derive a metallicity of -1.33^+0.19^-_0.01_dex and an age of 11.2^+1.8^_-0.8_Gyr. For some of the individual GCs and the stacked GC population, we derive consistent ages and metallicities. From the 11 confirmed globular clusters and using a Markov Chain Monte Carlo approach we derived a dynamical mass-to-light ratio of 4.2^+8.6^-_3.4_M/L. This is at the lower end of the luminosity-mass scaling relation defined by the Local Group dwarf galaxies. Furthermore, we couldn't confirm nor reject the possibility of a rotational component of the GC system. If present, this would further modify the inferred mass. Follow-up observations of the globular cluster population and of the stellar body of the galaxy are needed to assess whether this galaxy is lacking dark matter like it was suggested for the pair of dwarf galaxies in the field of NGC 1052, or if this is a miss-interpretation arising from systematic uncertainties of the method commonly used for these systems and the large uncertainties of the individual globular cluster velocities.
1713. MUSE observations SBS 0335-052E
ID:
ivo://CDS.VizieR/J/A+A/606/L11
Title:
MUSE observations SBS 0335-052E
Short Name:
J/A+A/606/L11
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report on the discovery of ionised gas filaments in the circum-galactic halo of the extremely metal-poor compact starburst SBS 0335-052E in a 1.5h integration with the MUSE integral-field spectrograph. We detect these features in H{alpha} and [OIII] emission down to a limiting surface-brightness of 5x10^-19^erg/s/cm^2^/arcsec^2^. The filaments have projected diameters of 2.1kpc and extend more than 9kpc to the north and north-west from the main stellar body. We also detect extended nebular HeII {lambda}4686 emission that brightens towards the north-west at the rim of a starburst driven super-shell. We also present a velocity field of the ionised gas. The filaments appear to connect seamlessly in velocity space to the kinematical disturbances caused by the shell. Similar to high-z star-forming galaxies, the ionised gas in this galaxy is dispersion dominated. We argue that the filaments were created via feedback from the starburst and that these ionised structures in the halo may act as escape channels for Lyman continuum radiation in this gas-rich system.
1714. MUSE-Wide DR1 - Simple Spectrum Access
ID:
ivo://lam.cesam.aspic/muse_wide_dr1/q/ssa
Title:
MUSE-Wide DR1 - Simple Spectrum Access
Short Name:
MUSEWIDE1 SSAP
Date:
24 Aug 2021 14:22:32
Publisher:
The CeSAM VO team
Description:
Spectra of MUSE-Wide (version 1.0) sources on GOODS-South field.
1715. MUSE-Wide+MUSE-Deep EWs of Lyman{alpha} emitters
ID:
ivo://CDS.VizieR/J/A+A/659/A183
Title:
MUSE-Wide+MUSE-Deep EWs of Lyman{alpha} emitters
Short Name:
J/A+A/659/A183
Date:
25 Mar 2022 09:08:03
Publisher:
CDS
Description:
The hydrogen Lyman{alpha} line is often the only measurable feature in optical spectra of high-redshift galaxies. Its shape and strength are influenced by radiative transfer processes and the properties of the underlying stellar population. High equivalent widths of several hundred {AA} are especially hard to explain by models and could point towards unusual stellar populations, for example with low metallicities, young stellar ages, and a top-heavy initial mass function. Other aspects influencing equivalent widths are the morphology of the galaxy and its gas properties. The aim of this study is to better understand the connection between the Lyman{alpha} rest-frame equivalent width (EW0) and spectral properties as well as ultraviolet (UV) continuum morphology by obtaining reliable EW0 histograms for a statistical sample of galaxies and by assessing the fraction of objects with large equivalent widths. We used integral field spectroscopy from the Multi Unit Spectroscopic Explorer (MUSE) combined with broad-band data from the Hubble Space Telescope (HST) to measure EW0 . We analysed the emission lines of 1920 Lyman{alpha} emitters (LAEs) detected in the full MUSE-Wide (one hour exposure time) and MUSE-Deep (ten hour exposure time) surveys and found UV continuum counterparts in archival HST data. We fitted the UV continuum photometric images using the Galfit software to gain morphological information on the rest-UV emission and fitted the spectra obtained from MUSE to determine the double peak fraction, asymmetry, full-width at half maximum, and flux of the Lyman{alpha} line. The two surveys show different histograms of Lyman{alpha} EW0 . In MUSE-Wide, 20% of objects have EW0>240{AA}, while this fraction is only 11% in MUSE-Deep and ~=16% for the full sample. This includes objects without HST continuum counterparts (one-third of our sample), for which we give lower limits for EW0. The object with the highest securely measured EW0 has EW0=589+/-193{AA} (the highest lower limit being EW0=4464{AA}). We investigate the connection between EW0 and Lyman{alpha} spectral or UV continuum morphological properties. The survey depth has to be taken into account when studying EW0 distributions. We find that in general, high EW0 objects can have a wide range of spectral and UV morphological properties, which might reflect that the underlying causes for high EW0 values are equally varied.
1716. MUSE-Wide survey: 831 emission line galaxies
ID:
ivo://CDS.VizieR/J/A+A/606/A12
Title:
MUSE-Wide survey: 831 emission line galaxies
Short Name:
J/A+A/606/A12
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a first instalment of the MUSE-Wide survey, covering an area of 22.2 arcmin^2^ (corresponding to ~20% of the final survey) in the CANDELS/Deep area of the Chandra Deep Field South. We use the MUSE integral field spectrograph at the ESO VLT to conduct a full-area spectroscopic mapping at a depth of 1h exposure time per 1-arcmin^2^ pointing. We searched for compact emission line objects using our newly developed LSDCat software based on a 3-D matched filtering approach, followed by interactive classification and redshift measurement of the sources. Our catalogue contains 831 distinct emission line galaxies with redshifts ranging from 0.04 to 6. Roughly one third (237) of the emission line sources are Lyman{alpha} emitting galaxies with 3<z<6, only four of which had previously measured spectroscopic redshifts. At lower redshifts 351 galaxies are detected primarily by their [OII] emission line (0.3<~z<~1.5), 189 by their [OIII] line (0.21<~z<~0.85), and 46 by their H{alpha} line (0.04<~z<~0.42). Comparing our spectroscopic redshifts to photometric redshift estimates from the literature, we find excellent agreement for z<1.5 with a median {Delta}z of only ~4x10^-4^ and an outlier rate of 6%, however a significant systematic offset of {Delta}z=0.26 and an outlier rate of 23% for Ly{alpha} emitters at z>3. Together with the catalogue we also release 1D PSF-weighted extracted spectra and small 3D datacubes centred on each of the 831 sources.
1717. Musket Ball Cluster redshift catalog
ID:
ivo://CDS.VizieR/J/ApJ/772/131
Title:
Musket Ball Cluster redshift catalog
Short Name:
J/ApJ/772/131
Date:
21 Oct 2021
Publisher:
CDS
Description:
Merging galaxy clusters have become one of the most important probes of dark matter, providing evidence for dark matter over modified gravity and even constraints on the dark matter self-interaction cross-section. To properly constrain the dark matter cross-section it is necessary to understand the dynamics of the merger, as the inferred cross-section is a function of both the velocity of the collision and the observed time since collision. While the best understanding of merging system dynamics comes from N-body simulations, these are computationally intensive and often explore only a limited volume of the merger phase space allowed by observed parameter uncertainty. Simple analytic models exist but the assumptions of these methods invalidate their results near the collision time, plus error propagation of the highly correlated merger parameters is unfeasible. To address these weaknesses I develop a Monte Carlo method to discern the properties of dissociative mergers and propagate the uncertainty of the measured cluster parameters in an accurate and Bayesian manner. I introduce this method, verify it against an existing hydrodynamic N-body simulation, and apply it to two known dissociative mergers: 1ES 0657-558 (Bullet Cluster) and DLSCL J0916.2+2951 (Musket Ball Cluster).
1718. MWC 314 spectroscopy
ID:
ivo://CDS.VizieR/J/A+AS/131/469
Title:
MWC 314 spectroscopy
Short Name:
J/A+AS/131/469
Date:
21 Oct 2021
Publisher:
CDS
Description:
The results of high-resolution optical spectroscopy obtained for a recently suggested LBV (luminous blue variable) candidate, MWC 314, are presented. Photospheric lines mostly of N II and S II have been found for the first time with a resolution of 0.4-0.8{AA}. They imply a N/O overabundance previously reported for AG and HR Car since no O II absorptions were detected. Nearly 400 emission lines have been identified in the spectrum between 4190 and 8864{AA} many of which appear double-peaked. No significant P Cygni type absorption components have been found for the optically thick Balmer lines. This suggests that the stellar wind of MWC 314 is non-spherical and the circumstellar envelope is viewed not edge on. The systemic velocity measured using the emission lines of ionized metals turned out to be 55km/s, which corresponds to a distance towards the object of 3.0+/-0.2kpc, according to the galactic rotation curve. Our analysis of the characteristics of both photospheric and wind lines resulted in an estimate of the object's T_eff_ of nearly 25000K, which, however, needs further improvement. The other stellar parameters were found to be as follows: Log(L_bol_/L_{sun}_)=6.1+/-0.3, R_star_=60^+30^_=10_R_{sun}_. Our study confirms that MWC 314 is one of the most luminous stars in the Milky Way.
1719. MWC 922 XSHOOTER spectra
ID:
ivo://CDS.VizieR/J/A+A/601/A69
Title:
MWC 922 XSHOOTER spectra
Short Name:
J/A+A/601/A69
Date:
21 Oct 2021
Publisher:
CDS
Description:
Medium-resolution echelle spectra of the Red Square Nebula surrounding the star MWC 922 are presented. The spectra have been obtained in 2010 and 2012 using the XSHOOTER spectrograph mounted on the Very Large Telescope (VLT) in Paranal, Chile. The spectrum covers a wavelength range between 300nm-2.5um and shows that the nebula is rich in emission lines. We aim to identify the emission lines and use them as a tool to determine the physical and chemical characteristics of the nebula. The emission lines are also used to put constraints on the structure of the nebula and on the nature of the central stars. We analyzed and identified emission lines that indicated that the Red Square Nebula consists of a low density bipolar outflow, eminent in the broad emission component seen in [FeII], as well as in P Cygni line profiles indicative of fast outflowing material. The narrow component in the [FeII] lines is most likely formed in the photosphere of a surrounding disk. Some of the emission lines show a pronounced double peaked profile, such as CaII, indicating an accretion disk in Keplerian rotation around the central star. [OI] emission lines are formed in the neutral atomic zone separating the ionized disk photosphere from the molecular gas in the interior of the disk, which is prominent in molecular CO emission in the near-IR. [NII] and [SII] emission clearly originates in a low density but fairly hot (7000-10000K) nebular environment. HI recombination lines trace the extended nebula as well as the photosphere of the disk.
1720. Naked active galactic nuclei
ID:
ivo://CDS.VizieR/J/A+A/424/519
Title:
Naked active galactic nuclei
Short Name:
J/A+A/424/519
Date:
21 Oct 2021
Publisher:
CDS
Description:
In this paper we report the discovery of a new class of active galactic nucleus in which although the nucleus is viewed directly, no broad emission lines are present. The results are based on a survey for AGN in which a sample of about 800 quasars and emission line galaxies were monitored yearly for 25 years. Among the emission line galaxies was the expected population of Seyfert 2 galaxies with only narrow forbidden lines in emission, and no broad lines. However, from the long term monitoring programme it was clear that some 10% of these were strongly variable with strong continuum emission. It is argued that these objects can only be Seyfert 1 galaxies in which the nucleus is viewed directly, but in which broad emission lines are completely absent. We compare these observations with other cases from the literature where the broad line region is reported to be weak or variable, and investigate the possibility that the absence of the broad line component is due to reddening. We conclude that this does not account for the observations, and that in these AGN the broad line region is absent. We also tentatively identify more luminous quasars from our sample where the broad emission lines also appear to be absent. The consequences of this for AGN models are discussed, and a case is made that we are seeing AGN in a transition stage between the fuel supply from a surrounding star cluster being cut off, and the nucleus becoming dormant.

Limit your search

more »

more »

more »

more »

more »