EMIR, the near-infrared camera and multi-object spectrograph for the GTC

Garzón, F.; Balcells, M.; Gallego, J.; Gry, C.; Guzmán, R.; Hammersley, P. L.; Herrero, A.; Muñoz–Tuñón, C.; Pelló, R.; Prieto, M.; Bourrec, É.; Cabello, C.; Cardiel, N.; González-Fernández, C.; Laporte, Nicolas; Milliard, B.; Pascual, S.; Patrick, L. R.; Patrón, J.; Ramírez-Alegría, S.; Streblyanska, A.

doi:10.1051/0004-6361/202244729

Cited by 7 publications

(1 citation statement)

References 18 publications

(10 reference statements)

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“…1) and these were performed with the NIR arm (10 200-24 750 Å) of the X-shooter Echelle spectrograph (Vernet et al 2011) attached to the Very Large Telescope (VLT; Cerro Paranal, Chile). The remaining ten observing epochs were obtained during radio-quiet phases using the EMIR spectrograph (Garzón et al 2022) at the 10.4-m Gran Telescopio Canarias (GTC; La Palma, Spain). Each of the VLT/X-shooter epochs consist of 16 exposures, with total exposure times ranging from 1920 to 2400 s, and a slit width of 0.9 arcsec, yielding a spectral resolution of ∼54 km s −1 .…”

Section: Nir Spectroscopymentioning

confidence: 99%

Fast infrared winds during the radio-loud and X-ray obscured stages of the black hole transient GRS 1915+105

Sánchez-Sierras,

Muñoz-Darias,

Motta

et al. 2023

A&A

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The black hole transient GRS 1915+105 entered a new phase of activity in 2018, generally characterised by low X-ray and radio fluxes. This phase has only been interrupted by episodes of strong and variable radio emission, where high levels of X-ray absorption local to the source were measured. We present 18 epochs of near-infrared spectroscopy (2018–2023) obtained with GTC/EMIR and VLT/X-shooter, spanning both radio-loud and radio-quiet periods. We demonstrate that radio-loud phases are characterised by strong P-Cygni line profiles, indicative of accretion disc winds with velocities of up to ∼3000 km s−1. This velocity is consistent with those measured in other black hole transients. It is also comparable to the velocity of the X-ray winds detected during the peak outburst phases in GRS 1915+105, reinforcing the idea that massive, multi-phase outflows are characteristic features of the largest and most powerful black hole accretion discs. Conversely, the evolution of the Brγ line profile during the radio-quiet phases follows the expected trend for accretion disc lines in a system that is gradually decreasing its intrinsic luminosity, exhibiting weaker intensities and more pronounced double-peaks.

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Section: Nir Spectroscopymentioning

confidence: 99%

Fast infrared winds during the radio-loud and X-ray obscured stages of the black hole transient GRS 1915+105

Sánchez-Sierras,

Muñoz-Darias,

Motta

et al. 2023

A&A

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A long-period radio transient active for three decades

Hurley‐Walker

Rea

McSweeney

et al. 2023

Nature

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Optical properties of Y dwarfs observed with the Gran Telescopio Canarias

Martín,

Zhang,

Lanchas

et al. 2024

A&A

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Our science goals are to characterise the optical properties of Y dwarfs and to study their consistency with theoretical models. A sample of five Y dwarfs was observed with three optical and near-infrared instruments at the 10.4\,m Gran Telescopio Canarias. Deep near-infrared ($J$- or $H$-band) and multicolour optical images ($z$-, $i$-, $r$-, $g$-, $u$-bands) of the five targets and a low-resolution far-red optical spectrum for one of the targets were obtained. One of the Y dwarfs, WISE J173835.53+273258.9 (Y0), was clearly detected in the optical ($z$- and $i$-bands) and another, WISE J182831.08+265037.7 (Y2), was detected only in the $z$-band. We measured the colours of our targets and found that the $z-J$ and $i-z$ colours of the Y dwarfs are bluer than those of mid- and late-T dwarfs. This optical blueing has been predicted by models, but our data indicates that it is sharper and happens at temperatures about 150 K warmer than expected. The culprit is the K I resonance doublet, which weakens more abruptly in the T- to Y-type transition than expected. Moreover, we show that the alkali resonance lines (Cs I and K I) are weaker in Y dwarfs than in T dwarfs; the far-red optical spectrum of WISE J173835.53+273258.9 is similar to that of late-T dwarfs, but with stronger methane and water features; and we noted the appearance of new absorption features that we propose could be due to hydrogen sulphide. Last but not least, in 2014, WISE J173835.53+273258.9 presented a bluer $i-z$ colour than in 2021 by a factor of 2.8 (significance of 2.5sigma ). Thanks to our deep optical images, we found that the 2014 $i$-band spectrum was contaminated by a galaxy bluer than the Y dwarf. The optical properties of Y dwarfs presented here pose new challenges to the modelling of grain sedimentation in extremely cool objects. The weakening of the very broad K I resonance doublet due to condensation in dust grains is more abrupt than theoretically anticipated. Consequently, the observed blueing of the $z-J$ and $i-z$ colours of Y dwarfs with respect to T dwarfs is more pronounced than predicted by models and could boost the potential of upcoming deep large-area optical surveys regarding their ability to detect extremely cool objects.

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EMIR, the near-infrared camera and multi-object spectrograph for the GTC

Cited by 7 publications

References 18 publications

Fast infrared winds during the radio-loud and X-ray obscured stages of the black hole transient GRS 1915+105

Fast infrared winds during the radio-loud and X-ray obscured stages of the black hole transient GRS 1915+105

A long-period radio transient active for three decades

Optical properties of Y dwarfs observed with the Gran Telescopio Canarias

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