scholarly journals The VMC survey – XLIV: Mapping metallicity trends in the large magellanic cloud using near-infrared passbands

2021 ◽  
Author(s):  
Samyaday Choudhury ◽  
Richard de Grijs ◽  
Kenji Bekki ◽  
Maria-Rosa L Cioni ◽  
Valentin D Ivanov ◽  
...  
Keyword(s):  
Near Infrared ◽  
Spiral Galaxies ◽  
High Spatial Resolution ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
Tidal Interactions ◽  
The Mean ◽  
Red Giant ◽  
Metallicity Distribution

Abstract We have derived high-spatial-resolution metallicity maps covering ∼105 deg2 across the Large Magellanic Cloud (LMC) using near-infrared passbands from the VISTA Survey of the Magellanic Clouds. We attempt to understand the metallicity distribution and gradients of the LMC up to a radius of ∼ 6 kpc. We identify red giant branch (RGB) stars in spatially distinct Y, (Y − Ks) colour–magnitude diagrams. In any of our selected subregions, the RGB slope is used as an indicator of the average metallicity, based on calibration to metallicity using spectroscopic data. The mean LMC metallicity is [Fe/H] = −0.42 dex (σ[Fe/H] = 0.04 dex). We find the bar to be mildly metal-rich compared with the outer disc, showing evidence of a shallow gradient in metallicity (−0.008 ± 0.001 dex kpc−1) from the galaxy’s centre to a radius of 6 kpc. Our results suggest that the LMC’s stellar bar is chemically similar to the bars found in large spiral galaxies. The LMC’s radial metallicity gradient is asymmetric. It is metal-poor and flatter towards the southwest, in the direction of the Bridge. This hints at mixing and/or distortion of the spatial metallicity distribution, presumably caused by tidal interactions between the Magellanic Clouds.

scholarly journals The VMC survey – XXXIX. Mapping metallicity trends in the Small Magellanic Cloud using near-infrared passbands

2020 ◽  
Vol 497 (3) ◽  
pp. 3746-3760
Author(s):  
Samyaday Choudhury ◽  
Richard de Grijs ◽  
Stefano Rubele ◽  
Kenji Bekki ◽  
Maria-Rosa L Cioni ◽  
...  
Keyword(s):  
Near Infrared ◽  
High Spatial Resolution ◽  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
Galactic Centre ◽  
Small Magellanic Cloud ◽  
The West ◽  
Tidal Interactions ◽  
Red Giant ◽  
Metallicity Distribution

ABSTRACT We have derived high-spatial-resolution metallicity maps covering ∼42 deg2 across the Small Magellanic Cloud (SMC) in an attempt to understand its metallicity distribution and gradients up to a radius of ∼4○. Using the near-infrared VISTA Survey of the Magellanic Clouds, our data cover a thrice larger area compared with previous studies. We identify red giant branch (RGB) stars in spatially distinct Y, (Y − Ks) colour–magnitude diagrams. In any of our selected subregions, the RGB slope is used as an indicator of the average metallicity, based on calibration to metallicity using spectroscopic data. The metallicity distribution across the SMC is unimodal and can be fitted by a Gaussian distribution with a peak at [Fe/H] = −0.97 dex (σ[Fe/H] = 0.05 dex). We find evidence of a shallow gradient in metallicity (−0.031 ± 0.005 dex deg−1) from the Galactic Centre to radii of 2○–2${_{.}^{\circ}}$5, followed by a flat metallicity trend from ∼3${_{.}^{\circ}}$5 to 4○. We find that the SMC’s metallicity gradient is radially asymmetric. It is flatter towards the east than to the west, hinting at mixing and/or distortion of the spatial metallicity distribution (within the inner 3○), presumably caused by tidal interactions between the Magellanic Clouds.

scholarly journals Metallicities of intermediate-age and old star clusters in the Large Magellanic Cloud

2009 ◽  
Vol 5 (S266) ◽  
pp. 446-446
Author(s):  
Arūnas Kučinskas ◽  
Vidas Dobrovolskas ◽  
Algimantas Černiauskas ◽  
Roma Lazauskaitė ◽  
Toshihiko Tanabé
Keyword(s):  
Near Infrared ◽  
Star Clusters ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Compelling Evidence ◽  
Cluster Sample ◽  
Global Cluster ◽  
Red Giant ◽  
Average Cluster ◽  
Metallicity Distribution

AbstractWe derive photometric metallicities for 56 intermediate-age and old star clusters in the Large Magellanic Cloud from the slopes of their red-giant branches in near-infrared color–magnitude diagrams (CMDs). The cluster sample covers the LMC bar and disk to a distance of ~2 kpc from the LMC center. The derived cluster metallicity distribution spans a range of [Fe/H] = +0.0 . . . 1.4 and is similar to the metallicity distribution of field stars. We find that the average cluster metallicities in certain fields of the LMC bar and disk may be different, but there seems to be no compelling evidence for a global cluster metallicity gradient in the LMC.

scholarly journals Planetary nebulae in the VISTA Magellanic Cloud (VMC) Survey

2011 ◽  
Vol 7 (S283) ◽  
pp. 444-445
Author(s):  
Brent Miszalski ◽  
Ralph Napiwotzki ◽  
Maria-Rosa L. Cioni ◽  
Martin A. T. Groenewegen ◽  
Jose M. Oliveira ◽  
...  
Keyword(s):  
Luminosity Function ◽  
Near Infrared ◽  
Planetary Nebulae ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
First Year ◽  
Complementary Role ◽  
Initial Results ◽  
Central Stars

AbstractThe multi-epoch YJKs sub-arcsecond photometry of the VMC survey provides a long anticipated deep near-infrared (NIR) window into further understanding the stellar populations of the Magellanic Clouds. The first year of observations consisted of six tiles covering ~9% of the Large Magellanic Cloud (LMC) survey region and contains 102 objects previously classified as planetary nebulae (PNe). A large proportion of the sample were found to be contaminated by non-PNe. These initial results underline the importance of establishing a clean catalogue of LMC PNe before they are applied in areas such as the planetary nebula luminosity function (PNLF) and searches for binary central stars. As the VMC survey progresses it will play a fundamental role in cleaning extant PN catalogues and a complementary role in the discovery of new PNe.

scholarly journals IRSF/SIRIUS near-infrared survey of the Magellanic Clouds: triggered star formation in N11 in the Large Magellanic Cloud

2006 ◽  
Vol 2 (S237) ◽  
pp. 423-423
Author(s):  
H. Hatano ◽  
R. Kadowaki ◽  
D. Kato ◽  
S. Sato ◽  
Keyword(s):  
Star Formation ◽  
Near Infrared ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
Infrared Survey

AbstractA near-infrared survey of the Magellanic Clouds has been carried out with IRSF/SIRIUS. As a part of the results, we present a study of triggered star formation in N11 in the LMC.

Breaking the age–metallicity degeneracy: The metallicity distribution and star formation history of the Large Magellanic Cloud

2008 ◽  
Vol 4 (S256) ◽  
pp. 263-268 ◽  
Author(s):  
Andrew A. Cole ◽  
Aaron J. Grocholski ◽  
Doug Geisler ◽  
Ata Sarajedini ◽  
Verne V. Smith ◽  
...  
Keyword(s):  
Star Formation ◽  
Near Infrared ◽  
Large Magellanic Cloud ◽  
Star Formation History ◽  
Red Giants ◽  
Formation History ◽  
History Of ◽  
Red Giant ◽  
Metallicity Distribution ◽  
Modelling Process

AbstractWe have obtained metallicities from near-infrared calcium triplet spectroscopy for nearly a thousand red giants in 28 fields spanning a range of radial distances from the center of the bar to near the tidal radius. We have used these data to investigate the radius-metallicity and age-metallicity relations. A powerful application of these data is in conjunction with the analysis of deep HST color–magnitude diagrams (CMDs). Most of the power in determining a robust star-formation history from a CMD comes from the main-sequence turnoff and subgiant branches. The age-metallicity degeneracy that results is largely broken by the red giant branch color, but theoretical model RGB colors remain uncertain. By incorporating the observed metallicity distribution function into the modelling process, a star-formation history with massively increased precision and accuracy can be derived. We incorporate the observed metallicity distribution of the LMC bar into a maximum-likelihood analysis of the bar CMD, and present a new star formation history and age–metallicity relation for the bar. The bar is certainly younger than the disk as a whole, and the most reliable estimates of its age are in the 5–6 Gyr range, when the mean gas abundance of the LMC had already increased to [Fe/H] ≳ −0.6. There is no obvious metallicity gradient among the old stars in the LMC disk out to a distance of 8–10 kpc, but the bar is more metal-rich than the disk by ≈0.1–0.2 dex. This is likely to be the result of the bar's younger average age. In both disk and bar, 95% of the red giants are more metal-rich than [Fe/H] = −1.2.

scholarly journals The VMC survey – XXXVI. Young stellar variability in the Large Magellanic Cloud

2020 ◽  
Vol 494 (1) ◽  
pp. 458-486 ◽  
Author(s):  
Viktor Zivkov ◽  
Joana M Oliveira ◽  
Monika G Petr-Gotzens ◽  
Stefano Rubele ◽  
Maria-Rosa L Cioni ◽  
...  
Keyword(s):  
Near Infrared ◽  
High Reliability ◽  
Large Magellanic Cloud ◽  
Systematic Investigation ◽  
Variable Stars ◽  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
Light Curves ◽  
Young Stellar Objects ◽  
Photometric Variability

ABSTRACT Studies of young stellar objects (YSOs) in the Galaxy have found that a significant fraction exhibits photometric variability. However, no systematic investigation has been conducted on the variability of extragalactic YSOs. Here we present the first variability study of massive YSOs in an $\sim 1.5\, \mathrm{deg^2}$ region of the Large Magellanic Cloud (LMC). The aim is to investigate whether the different environmental conditions in the metal-poor LMC ($\sim 0.4\!-\!0.5\, \mathrm{Z_{\odot }}$) have an impact on the variability characteristics. Multi-epoch near-infrared (NIR) photometry was obtained from the VISTA Survey of the Magellanic Clouds (VMC) and our own monitoring campaign using the VISTA telescope. By applying a reduced χ2-analysis, stellar variability was identified. We found 3062 candidate variable stars from a population of 362 425 stars detected. Based on several Spitzer studies, we compiled a sample of high-reliability massive YSOs: a total of 173 massive YSOs have NIR counterparts (down to $K_s\sim 18.5\,$mag) in the VMC catalogue, of which 39 display significant (>3σ) variability. They have been classified as eruptive, fader, dipper, short-term variable, and long-period variable YSOs based mostly on the appearance of their Ks-band light curves. The majority of YSOs are aperiodic; only five YSOs exhibit periodic light curves. The observed amplitudes are comparable or smaller than those for Galactic YSOs (only two Magellanic YSOs exhibit $\Delta K_s\gt 1\,$mag), not what would have been expected from the typically larger mass accretion rates observed in the Magellanic Clouds.

scholarly journals Tidal interactions between the Galaxy and the Magellanic Clouds

1985 ◽  
Vol 106 ◽  
pp. 477-478 ◽  
Author(s):  
N. Ramamani ◽  
T. Meinya Singh ◽  
Saleh Mohammed Alladin
Keyword(s):  
Adiabatic Approximation ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
Tidal Interactions ◽  
The Galaxy ◽  
Binary Galaxy ◽  
Disruption Time

The merging time and the disruption time in a binary galaxy system are analytically obtained under the Adiabatic Approximation (AA). Applications are made to the Galaxy-LMC (Large Magellanic Cloud) pair.

scholarly journals Morphology of stellar populations in the Magellanic Clouds using the VMC survey

2018 ◽  
Vol 14 (S344) ◽  
pp. 66-69
Author(s):  
Dalal El Youssoufi ◽  
Maria-Rosa L. Cioni ◽  
Cameron P. M. Bell ◽  
Stefano Rubele ◽  
Florian Niederhofer ◽  
...  
Keyword(s):  
Near Infrared ◽  
Milky Way ◽  
Stellar Populations ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
Galaxy Interactions ◽  
Irregular Galaxies ◽  
History Of ◽  
Interaction History

AbstractThe Magellanic Clouds are nearby dwarf irregular galaxies that represent a unique laboratory for studying galaxy interactions. Their morphology and dynamics have been heavily influenced by their mutual interactions as well as with their interaction(s) with the Milky Way. We use the VISTA near-infrared YJKs survey of the Magellanic Clouds system (VMC) in combination with stellar partial models of the Large Magellanic Cloud (LMC), the Small Magellanic Cloud (SMC) and the Milky Way to investigate the spatial distribution of stellar populations of different ages across the Magellanic Clouds. In this contribution, we present the results of these studies that allow us to trace substructures possibly related to the interaction history of the Magellanic Clouds.

scholarly journals The Near-infrared Tip of the Red Giant Branch. II. An Absolute Calibration in the Large Magellanic Cloud

2018 ◽  
Vol 858 (1) ◽  
pp. 12 ◽  
Author(s):  
Taylor J. Hoyt ◽  
Wendy L. Freedman ◽  
Barry F. Madore ◽  
Mark Seibert ◽  
Rachael L. Beaton ◽  
...  
Keyword(s):  
Near Infrared ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Absolute Calibration ◽  
Red Giant
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