Lucky Spectroscopy, an equivalent technique to Lucky Imaging

Apellániz, J. Maíz; Barbá, R. H.; Fariña, C.; Sota, A.; González, M. Pantaleoni; Holgado, G.; Negueruela, I.; Diaz, Sébastien

doi:10.1051/0004-6361/201832885

Cited by 36 publications

(44 citation statements)

References 27 publications

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“…where P V J (λ) is the total-system dimensionless sensitivity function, f λ (λ) is the spectral energy distribution (SED) of the object, f λ,Vega (λ) is the Vega SED, and ZP V J is the photometric zeropoint (Maíz Apellániz 2005, 2006, 2007. If the equivalent unextinguished SED, f λ,0 (λ) has a Johnson V J magnitude of V J,0 , then the extinction in that filter, A V J , can be expressed as…”

Section: Discussionmentioning

confidence: 99%

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Optical-NIR dust extinction towards Galactic O stars

Apellániz

Barbá

2018

A&A

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Context. O stars are excellent tracers of the intervening ISM because of their high luminosity, blue intrinsic SED, and relatively featureless spectra. We are currently conducting the Galactic O-Star Spectroscopic Survey (GOSSS), which is generating a large sample of O stars with accurate spectral types within several kpc of the Sun. Aims. We aim to obtain a global picture of the properties of dust extinction in the solar neighborhood based on optical-NIR photometry of O stars with accurate spectral types. Methods. We have processed a carefully selected photometric set with the CHORIZOS code to measure the amount [E(4405 − 5495)] and type [R 5495 ] of extinction towards 562 O-type stellar systems. We have tested three different families of extinction laws and analyzed our results with the help of additional archival data. Results. The Maíz Apellániz et al. (2014, A&A 564, A63) family of extinction laws provides a better description of Galactic dust that either the Cardelli et al. , ApJ 345, 245) or Fitzpatrick (1999 families, so it should be preferentially used when analyzing samples similar to the one in this paper. In many cases O stars and late-type stars experience similar amounts of extinction at similar distances but some O stars are located close to the molecular clouds left over from their births and have larger extinctions than the average for nearby late-type populations. In qualitative terms, O stars experience a more diverse extinction than late-type stars, as some are affected by the small-grain-size, low-R 5495 effect of molecular clouds and others by the large-grain-size, high-R 5495 effect of H ii regions. Late-type stars experience a narrower range of grain sizes or R 5495 , as their extinction is predominantly caused by the average, diffuse ISM. We propose that the reason for the existence of large-grain-size, high-R 5495 regions in the ISM in the form of H ii regions and hot-gas bubbles is the selective destruction of small dust grains by EUV photons and possibly by thermal sputtering by atoms or ions.

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Section: Discussionmentioning

confidence: 99%

“…Here we have possible zero-point errors and discrepancies between different photometric sources. As previously mentioned, we have minimized those problems by analyzing the zero points in different systems (Maíz Apellániz 2005, 2006, 2007 and by assigning quality flags (and associated uncertainties) to different sources. -SED.…”

Section: Methodsmentioning

confidence: 99%

Optical-NIR dust extinction towards Galactic O stars

Apellániz

Barbá

2018

A&A

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“…We have been recently successful (Maíz Apellániz et al 2018a) in applying a new technique, lucky spectroscopy, to spatially separate close visual components in GOSSS data, which is used for five of the systems in this paper (MY Cam A+B, LY Aur A+B, δ Ori Aa+Ab, ζ Ori AaAb+B, and σ Ori AaAb+B). The first two of those systems did not appear in Maíz Apellániz et al (2018a) and for the last one we have repeated the observations and obtained new data. LY Aur A and MY Cam A are fainter targets than the other three and that led us to observe them with a different setup.…”

Section: Gosss Datamentioning

confidence: 99%

MONOS: Multiplicity Of Northern O-type Spectroscopic systems

Apellániz

Paez

Negueruela

et al. 2019

A&A

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Context. Multiplicity in massive stars is key to understanding the chemical and dynamical evolution of galaxies. Among massive stars, those of O type play a crucial role due to their high masses and short lifetimes. Aims. MONOS (Multiplicity Of Northern O-type Spectroscopic systems) is a project designed to collect information and study O-type spectroscopic binaries with δ > −20 • . In this first paper we describe the sample and provide spectral classifications and additional information for objects with previous spectroscopic and/or eclipsing binary orbits. In future papers we will test the validity of previous solutions and calculate new spectroscopic orbits. Methods. The spectra in this paper have two sources: the Galactic O-Star Spectroscopic Survey (GOSSS), a project that obtains blueviolet R ∼ 2500 spectroscopy of thousands of massive stars, and LiLiMaRlin, a library of libraries of high-resolution spectroscopy of massive stars obtained from four different surveys (CAFÉ-BEANS, OWN, IACOB, and NoMaDS) and additional data from our own observing programs and public archives. We have also used lucky images obtained with AstraLux. Results. We present homogeneous spectral classifications for 92 O-type spectroscopic multiple systems and ten optical companions, many of them original. We discuss the visual multiplicity of each system with the support of AstraLux images and additional sources. For eleven O-type objects and for six B-type objects we present their first GOSSS spectral classifications. For two known eclipsing binaries we detect double absorption lines (SB2) or a single moving line (SB1) for the first time, to which we add a third system reported by us recently. For two previous SB1 systems we detect their SB2 nature for the first time and give their first separate spectral classifications, something we have also done for a third object just recently identified as a SB2. We also detect nine new astrometric companions and provide updated information on several others. We emphasize the results for two stars: for σ Ori AaAbB we provide spectral classifications for the three components with a single observation for the first time thanks to a lucky spectroscopy observation obtained close to the Aa,Ab periastron and for θ 1 Ori CaCb we add it to the class of Galactic Of?p stars, raising the number of its members to six. Our sample of O-type spectroscopic binaries contains more triple-or higher-order systems than double systems.

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“…The technique we apply in this paper has been used in the past (Maíz Apellániz 2005a, 2006, 2017 to test different photometric systems. We compute the synthetic photometry of stars observed with high-quality HST spectrophotometry and we compare it with the observed photometry.…”

Section: New 2mass Vega Zero Points From Calspecmentioning

confidence: 99%

A reevaluation of the 2MASS zero points using CALSPEC spectrophotometry complemented with Gaia Data Release 2 parallaxes

Apellániz¹,

González²

2018

A&A

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Context. 2MASS is the reference survey in the NIR part of the spectrum given its whole-sky coverage, large dynamic range, and proven calibration uniformity. However, previous studies disagree in the value of the zero points (ZPs) for its three bands JHK at the hundredth of a magnitude level. The disagreement should become more noticeable now that Gaia provides whole-sky optical photometry calibrated below that level. Aims. We want to establish the value of the 2MASS ZPs based on NICMOS/HST spectrophotometry of the CALSPEC standard stars and test it with the help of Gaia DR2 parallaxes. Methods. We have computed the synthetic JHK photometry for a sample of stars using the HST CALSPEC spectroscopic standards and compared it with their 2MASS magnitudes to evaluate the ZPs. We have tested our results by analysing a sample of FGK dwarfs with excellent 2MASS photometry and accurate Gaia DR2 parallaxes. Results. The Vega ZPs for 2MASS J, H, and K are found to be −0.025 ± 0.005 mag, 0.004 ± 0.005 mag, and −0.015 ± 0.005 mag, respectively. The analysis of FGK sample indicates that the new ZPs are more accurate than previous ones.

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Lucky Spectroscopy, an equivalent technique to Lucky Imaging

Cited by 36 publications

References 27 publications

Optical-NIR dust extinction towards Galactic O stars

Optical-NIR dust extinction towards Galactic O stars

MONOS: Multiplicity Of Northern O-type Spectroscopic systems

A reevaluation of the 2MASS zero points using CALSPEC spectrophotometry complemented with Gaia Data Release 2 parallaxes

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