Unidentified emission features in the R Coronae Borealis star V854 Centauri

During its 2012 decline, the R Coronae Borealis star (RCB) V854 Cen was spectroscopically monitored with X-shooter on the ESO Very Large Telescope. The obscured optical and near-infrared spectrum exhibits many narrow and several broad emission features, as previously observed. The envelope is spatially resolved along the slit and allows for a detailed study of the circumstellar material. In this Letter, we report on the properties of a number of unidentified visual emission features (UFs), including the detection of a new feature at 8692 Å. These UFs have been observed in the Red Rectangle (RR), but their chemical and physical nature is still a mystery. The previously known UFs behave similarly in the RR and in V854 Cen, but are not detected in six other observed RCBs. Some hydrogen might be required for the formation of their carrier(s). The λ8692 UF is present in all RCBs. Its carrier is likely of a carbonaceous molecular nature, presumably different from that of the other UFs.

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Very Large Telescope near-infrared spectra of hard serendipitous Chandra sources

Monthly Notices of the Royal Astronomical Society ◽

10.1046/j.1365-8711.2002.05805.x ◽

2002 ◽

Vol 337 (3) ◽

pp. 781-794 ◽

Cited By ~ 7

Author(s):

P. Gandhi ◽

C. S. Crawford ◽

A. C. Fabian

Keyword(s):

Infrared Spectra ◽

Near Infrared ◽

Large Telescope ◽

Very Large Telescope ◽

Near Infrared Spectra

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Lithium abundance in lower red giant branch stars of Omega Centauri

Astronomy and Astrophysics ◽

10.1051/0004-6361/201833457 ◽

2018 ◽

Vol 618 ◽

pp. A134 ◽

Cited By ~ 5

Author(s):

A. Mucciarelli ◽

M. Salaris ◽

L. Monaco ◽

P. Bonifacio ◽

X. Fu ◽

...

Keyword(s):

High Resolution ◽

Globular Clusters ◽

Stellar System ◽

The Other ◽

Large Telescope ◽

Lithium Abundance ◽

Very Large Telescope ◽

Red Giant ◽

Giant Branch Stars ◽

Branch Star

We present Li, Na, Al, and Fe abundances of 199 lower red giant branch star members of the stellar system Omega Centauri, using high-resolution spectra acquired with FLAMES at the Very Large Telescope. The A(Li) distribution is peaked at A(Li) ∼ 1 dex with a prominent tail towards lower values. The peak of the distribution well agrees with the lithium abundances measured in lower red giant branch stars in globular clusters and Galactic field stars. Stars with A(Li) ∼ 1 dex are found at metallicities lower than [Fe/H] ∼ –1.3 dex but they disappear at higher metallicities. On the other hand, Li-poor stars are found at all metallicities. The most metal-poor stars exhibit a clear Li–Na anti-correlation, where about 30% of the sample have A(Li) lower than ∼0.8 dex, while these stars represent a small fraction of normal globular clusters. Most of the stars with [Fe/H] > –1.6 dex are Li poor and Na rich. The Li depletion measured in these stars is not observed in globular clusters with similar metallicities and we demonstrate that it is not caused by the proposed helium enhancements and/or young ages. Hence, these stars formed from a gas already depleted in lithium. Finally, we note that Omega Centauri includes all the populations (Li-normal/Na-normal, Li-normal/Na-rich, and Li-poor/Na-rich stars) observed, to a lesser extent, in mono-metallic GCs.

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The dwarf planet Makemake as seen by X-Shooter

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa2329 ◽

2020 ◽

Vol 497 (4) ◽

pp. 5473-5479

Author(s):

Alvaro Alvarez-Candal ◽

Ana Carolina Souza-Feliciano ◽

Walter Martins-Filho ◽

Noemí Pinilla-Alonso ◽

José Luis Ortiz

Keyword(s):

Infrared Spectrum ◽

Near Infrared ◽

Resolving Power ◽

Large Telescope ◽

Very Large Telescope ◽

Absorption Features ◽

Near Infrared Spectrum

ABSTRACT Makemake is one of the brightest known trans-Neptunian objects, as such, it has been widely observed. Nevertheless, its visibility to near-infrared spectrum has not been completely observed in medium-resolving power, aimed at studying in detail the absorption features of CH4 ice. In this paper, we present the spectrum of Makemake observed with X-Shooter at the Very Large Telescope (Chile). We analyse the detected features, measuring their location and depth. Furthermore, we compare Makemake’s spectrum with that of Eris, obtained with the same instrument and similar setup, to conclude that the bands of the CH4 ice in both objects show similar shifts.

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PROSPECTS FOR TESTING THE NATURE OF Sgr A*'s NEAR-INFRARED FLARES ON THE BASIS OF CURRENT VERY LARGE TELESCOPE—AND FUTURE VERY LARGE TELESCOPE INTERFEROMETER—OBSERVATIONS

The Astrophysical Journal ◽

10.1088/0004-637x/692/1/902 ◽

2009 ◽

Vol 692 (1) ◽

pp. 902-916 ◽

Cited By ~ 45

Author(s):

N. Hamaus ◽

T. Paumard ◽

T. Müller ◽

S. Gillessen ◽

F. Eisenhauer ◽

...

Keyword(s):

Near Infrared ◽

Large Telescope ◽

Very Large Telescope ◽

Sgr A

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Polarimetry of relativistic tidal disruption event Swift J2058+0516

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz3106 ◽

2019 ◽

Vol 491 (2) ◽

pp. 1771-1776 ◽

Cited By ~ 2

Author(s):

K Wiersema ◽

A B Higgins ◽

A J Levan ◽

R A J Eyles ◽

R L C Starling ◽

...

Keyword(s):

Linear Polarization ◽

Near Infrared ◽

Thermal Emission ◽

Large Telescope ◽

Relativistic Jets ◽

Tidal Disruption ◽

Very Large Telescope ◽

Wide Range ◽

Independent Test ◽

Show Evidence

ABSTRACT A small fraction of candidate tidal disruption events (TDEs) show evidence of powerful relativistic jets, which are particularly pronounced at radio wavelengths, and likely contribute non-thermal emission at a wide range of wavelengths. A non-thermal emission component can be diagnosed using linear polarimetry, even when the total received light is dominated by emission from an accretion disc or disc outflow. In this paper, we present Very Large Telescope (VLT) measurements of the linear polarization of the optical light of jetted TDE Swift J2058+0516. This is the second jetted TDE studied in this manner, after Swift J1644+57. We find evidence of non-zero optical linear polarization, $P_{V}\sim 8{{\, \rm per\, cent}}$, a level very similar to the near-infrared polarimetry of Swift J1644+57. These detections provide an independent test of the emission mechanisms of the multiwavelength emission of jetted TDEs.

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