The VMC Survey

Cioni, M. R. L.; Kamath, D.; Rubele, Stefano; Loon, Jacco Th. van; Wood, P. R.; Emerson, J. P.; Gibson, Brad K.; Groenewegen, M. A. T.; Ivanov, V. D.; Miszalski, B.; Ripepi, V.

doi:10.1051/0004-6361/201219696

Cited by 24 publications

(33 citation statements)

References 70 publications

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“…5.4, but there may be an additional effect due to the calibration using quasars and galaxies because the two types of objects have different mean colours (see e.g. Cioni et al 2013). Our proper motion for the SMC Red is dominated by stars in the red clump and RGB phases which typically have ages between 1 Gyr and a few Gyr.…”

Section: Comparison To Previous Measurementsmentioning

confidence: 96%

The VMC survey

Cioni

Bekki

Girardi

et al. 2016

A&A

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Aims. In this study we use multi-epoch near-infrared observations from the VISTA survey of the Magellanic Cloud system (VMC) to measure the proper motions of different stellar populations in a tile of 1.5 deg 2 in size in the direction of the Galactic globular cluster 47 Tuc. We obtain the proper motion of the cluster itself, of the Small Magellanic Cloud (SMC), and of the field Milky Way stars. Methods. Stars of the three main stellar components are selected according to their spatial distributions and their distributions in colour−magnitude diagrams. Their average coordinate displacement is computed from the difference between multiple K s -band observations for stars as faint as K s = 19 mag. Proper motions are derived from the slope of the best-fitting line among ten VMC epochs over a time baseline of ∼1 yr. Background galaxies are used to calibrate the absolute astrometric reference frame. Results. The resulting absolute proper motion of 47 Tuc is (μ α cos(δ), μ δ ) = (+7.26 ± 0.03, −1.25 ± 0.03) mas yr −1 . This measurement refers to about 35 000 sources distributed between 10 and 60 from the cluster centre. For the SMC we obtain (μ α cos(δ), μ δ ) = (+1.16 ± 0.07, −0.81 ± 0.07) mas yr −1 from about 5250 red clump and red giant branch stars. The absolute proper motion of the Milky Way population in the line of sight (l = 305.9, b = −44.9) of this VISTA tile is (μ α cos(δ), μ δ ) = (+10.22 ± 0.14, −1.27 ± 0.12) mas yr −1 and has been calculated from about 4000 sources. Systematic uncertainties associated with the astrometric reference system are 0.18 mas yr −1 . Thanks to the proper motion we detect 47 Tuc stars beyond its tidal radius.

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Section: Comparison To Previous Measurementsmentioning

confidence: 96%

The VMC survey

Cioni

Bekki

Girardi

et al. 2016

A&A

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“…Field 1973;Vanden Berk et al 2001). Some of the background galaxies and QSOs identified in this study have been published in Cioni et al (2013). The full sample of background galaxies and QSOs will be discussed in a following publication.…”

Section: Preliminary Spectral Classificationmentioning

confidence: 99%

Optically visible post-AGB stars, post-RGB stars and young stellar objects in the Large Magellanic Cloud

Kamath¹,

Wood²,

Winckel³

2015

Mon. Not. R. Astron. Soc.

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125

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We have carried out a search for optically visible post-Asymptotic Giant Branch (post-AGB) stars in the Large Magellanic Cloud (LMC). First, we selected candidates with a mid-IR excess and then obtained their optical spectra. We disentangled contaminants with unique spectra such as M-stars, C-stars, planetary nebulae, quasi-stellar objects and background galaxies. Subsequently, we performed a detailed spectroscopic analysis of the remaining candidates to estimate their stellar parameters such as effective temperature, surface gravity (log g), metallicity ([Fe/H]), reddening and their luminosities. This resulted in a sample of 35 likely post-AGB candidates with late-G to late-A spectral types, low log g, and [Fe/H] < −0.5. Furthermore, our study confirmed the existence of the dusty post-Red Giant Branch (post-RGB) stars, discovered previously in our SMC survey, by revealing 119 such objects in the LMC. These objects have mid-IR excesses and stellar parameters (T eff , log g, [Fe/H]) similar to those of post-AGB stars except that their luminosities (< 2500 L ), and hence masses and radii, are lower. These post-RGB stars are likely to be products of binary interaction on the RGB. The post-AGB and post-RGB objects show SED properties similar to the Galactic post-AGB stars, where some have a surrounding circumstellar shell, while some others have a surrounding stable disc similar to the Galactic post-AGB binaries. This study also resulted in a new sample of 162 young stellar objects, identified based on a robust log g criterion. Other interesting outcomes include objects with an UV continuum and an emission line spectrum; luminous supergiants; hot main-sequence stars; and 15 B[e] star candidates, 12 of which are newly discovered in this study.

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“…Some contamination from young stellar objects, brown dwarfs, planetary nebulae, and post-AGB stars is expected. Cioni et al (2013) estimated that the total number of quasars with Y < 19.32 mag, J < 19.09 mag, and K s < 18.04 mag is 1200 behind the LMC, 400 behind the SMC, 200 behind the Bridge, and 30 behind the Stream. Figure 1 shows the location of all confirmed quasars from the MQS and Table 1.…”

Section: Sample Selectionmentioning

confidence: 99%

“…The Magellanic Clouds system is an extreme case where these obstacles are notably enhanced: the combined area of the two galaxies, the Magellanic Bridge, and the Stream that connects them with the Milky Way is at least two hundred square degrees; the significant depth of the Small Magellanic Cloud (SMC) along the line of sight (e.g., de Grijs & Bono 2015) aggravates the contamination and reddening issues. Cioni et al (2013) reviewed previous works aiming at discovering quasars behind the Magellanic Clouds: Blanco & Heathcote (1986), Dobrzycki et al (2002Dobrzycki et al ( , 2003bDobrzycki et al ( ,a, 2005, Geha et al (2003), Kozłowski & Kochanek (2009), Kozłowski et al (2012), and Véron-Cetty & Véron (2010. In this study we add the latest installment of the Magellanic Quasar Survey (MQS) by Kozłowski et al (2013), who increased the number of spectroscopically confirmed quasars behind the Large Magellanic Cloud (LMC) and SMC to 758, almost an order of a magnitude higher than before.…”

Section: Introductionmentioning

confidence: 99%

New quasars behind the Magellanic Clouds. Spectroscopic confirmation of near-infrared selected candidates

Ivanov

Cioni

Bekki

et al. 2016

A&A

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Context. Quasi-stellar objects (quasars) located behind nearby galaxies provide an excellent absolute reference system for astrometric studies, but they are difficult to identify because of fore-and background contamination. Deep wide-field, high angular resolution surveys spanning the entire area of nearby galaxies are needed to obtain a complete census of such quasars. Aims. We embarked on a program to expand the quasar reference system behind the Large and the Small Magellanic Clouds, the Magellanic Bridge, and the Magellanic Stream that connects the Clouds with the Milky Way. Methods. Hundreds of quasar candidates were selected based on their near-infrared colors and variability properties from the ongoing public ESO VISTA Magellanic Clouds survey. A subset of 49 objects was followed up with optical spectroscopy. Results. We confirmed the quasar nature of 37 objects (34 new identifications): four are low redshift objects, three are probably stars, and the remaining three lack prominent spectral features for a secure classification. The bona fide quasars, identified from their broad emisison lines, are located as follows: 10 behind the LMC, 13 behind the SMC, and 14 behind the Bridge. The quasars span a redshift range from z ∼ 0.5 to z ∼ 4.1. Conclusions. Upon completion the VMC survey is expected to yield a total of ∼1500 quasars with Y < 19.32 mag, J < 19.09 mag, and K s < 18.04 mag.

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The VMC Survey

Cited by 24 publications

References 70 publications

The VMC survey

The VMC survey

Optically visible post-AGB stars, post-RGB stars and young stellar objects in the Large Magellanic Cloud

New quasars behind the Magellanic Clouds. Spectroscopic confirmation of near-infrared selected candidates

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