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 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 A near-infrared VISTA of the Small Magellanic Cloud

2018 ◽  
Vol 14 (S344) ◽  
pp. 53-56
Author(s):  
Maria-Rosa L. Cioni ◽  
Florian Niederhofer ◽  
Stefano Rubele ◽  
Ning-Chen Sun
Keyword(s):  
Near Infrared ◽  
Stellar Populations ◽  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
Level Of Detail ◽  
Star Formation History ◽  
Main Body ◽  
Small Magellanic Cloud ◽  
Formation History ◽  
The Galaxy

AbstractVISTA observed the Small Magellanic Cloud (SMC), as part of the VISTA survey of the Magellanic Clouds system (VMC), for six years (2010–2016). The acquired multi-epoch YJKs images have allowed us to probe the stellar populations to an exceptional level of detail across an unprecedented wide area in the near-infrared. This contribution highlights the most recent VMC results obtained on the SMC focusing, in particular, on the clustering of young stellar populations, on the proper motion of stars in the main body of the galaxy and on the spatial distribution of the star formation history.

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 A near infrared variable star survey in the Magellanic Clouds: The Small Magellanic Cloud data

2018 ◽  
Author(s):  
Yoshifusa Ita ◽  
Noriyuki Matsunaga ◽  
Toshihiko Tanabé ◽  
Yoshikazu Nakada ◽  
Daisuke Kato ◽  
...  
Keyword(s):  
Near Infrared ◽  
Variable Star ◽  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
Small Magellanic Cloud ◽  
Cloud Data

scholarly journals Presence of red giant population in the foreground stellar sub-structure of the Small Magellanic Cloud

2021 ◽  
Author(s):  
Dizna James ◽  
Smitha Subramanian ◽  
Abinaya O Omkumar ◽  
Adhya Mary ◽  
Kenji Bekki ◽  
...  
Keyword(s):  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
Eastern Region ◽  
Main Body ◽  
Small Magellanic Cloud ◽  
Similar Distance ◽  
Red Clump ◽  
Red Giant ◽  
Astrometric Data ◽  
Recent Epoch

Abstract The eastern region of the Small Magellanic Cloud (SMC) is found to have a foreground stellar sub-structure, which is identified as a distance bimodality (∼ 12 kpc apart) in the previous studies using Red Clump (RC) stars. Interestingly, studies of Red Giant Branch (RGB) stars in the eastern SMC indicate a bimodal radial velocity (RV) distribution. In this study, we investigate the connection between these two bimodal distributions to better understand the nature and origin of the foreground stellar sub-structure in the eastern SMC. We use the Gaia EDR3 astrometric data and archival RV data of RGB stars for this study. We found a bimodal RV distribution of RGB stars (separated by ∼ 35–45 km s−1) in the eastern and south-western (SW) outer regions. The observed proper motion values of the lower and higher RV RGB components in the eastern regions are similar to those of the foreground and main-body RC stars respectively. This suggests that the two RGB populations in the eastern region are separated by a similar distance as those of the RC stars, and the RGB stars in the lower RV component are part of the foreground sub-structure. Based on the differences in the distance and RV of the two components, we estimated an approximate time of formation of this sub-structure as 307 ± 65 Myr ago. This is comparable with the values predicted by simulations for the recent epoch of tidal interaction between the Magellanic Clouds. Comparison of the observed properties of RGB stars, in the outer SW region, with N-body simulations shows that the higher RV component in the SW region is at a farther distance than the main body, indicating the presence of a stellar Counter-Bridge in the SW region of the SMC.

scholarly journals The intrinsic reddening of the Magellanic Clouds as traced by background galaxies – I. The bar and outskirts of the Small Magellanic Cloud

2019 ◽  
Vol 489 (3) ◽  
pp. 3200-3217
Author(s):  
Cameron P M Bell ◽  
Maria-Rosa L Cioni ◽  
A H Wright ◽  
Stefano Rubele ◽  
David L Nidever ◽  
...  
Keyword(s):  
Near Infrared ◽  
Broad Band ◽  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
Spectral Energy ◽  
Small Magellanic Cloud ◽  
Energy Distributions ◽  
Stellar Objects ◽  
Quasi Stellar Objects ◽  
Low Levels

ABSTRACT We present a method to map the total intrinsic reddening of a foreground extinguishing medium via the analysis of spectral energy distributions (SEDs) of background galaxies. In this pilot study, we implement this technique in two distinct regions of the Small Magellanic Cloud (SMC) – the bar and the southern outskirts – using a combination of optical and near-infrared ugrizYJKs broad-band imaging. We adopt the lephare χ2-minimization SED-fitting routine and various samples of galaxies and/or quasi-stellar objects to investigate the intrinsic reddening. We find that only when we construct reddening maps using objects classified as galaxies with low levels of intrinsic reddening (i.e. ellipticals/lenticulars and early-type spirals), the resultant maps are consistent with previous literature determinations, i.e. the intrinsic reddening of the SMC bar is higher than that in the outer environs. We employ two sets of galaxy templates – one theoretical and one empirical – to test for template dependences in the resulting reddening maps and find that the theoretical templates imply systematically higher reddening values by up to 0.20 mag in E(B − V). A comparison with previous reddening maps, based on the stellar components of the SMC, typically shows reasonable agreement. There is, however, significant variation amongst the literature reddening maps as to the level of intrinsic reddening associated with the bar. Thus, it is difficult to unambiguously state that instances of significant discrepancies are the result of appreciable levels of dust not accounted for in some literature reddening maps or whether they reflect issues with our adopted methodology.

scholarly journals An overview of the structure and kinematics of the Magellanic Clouds

1991 ◽  
Vol 148 ◽  
pp. 15-23 ◽  
Author(s):  
B. E. Westerlund
Keyword(s):  
Star Formation ◽  
Observational Data ◽  
Spiral Structure ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
Line Of Sight ◽  
Small Magellanic Cloud ◽  
Complex Velocity ◽  
The Past

A vast amount of observational data concerning the structure and kinematics of the Magellanic Clouds is now available. Many basic quantities (e.g. distances and geometry) are, however, not yet sufficiently well determined. Interactions between the Small Magellanic Cloud (SMC), the Large Magellanic Cloud (LMC) and our Galaxy have dominated the evolution of the Clouds, causing bursts of star formation which, together with stochastic self-propagating star formation, produced the observed structures. In the youngest generation in the LMC it is seen as an intricate pattern imitating a fragmented spiral structure. In the SMC much of the fragmentation is along the line of sight complicating the reconstruction of its history. The violent events in the past are also recognizable in complex velocity patterns which make the analysis of the kinematics of the Clouds difficult.

scholarly journals UVIT-HST-Gaia-VISTA study of KRON 3 in the Small Magellanic Cloud: A cluster with an extended red clump in UV

2021 ◽  
Author(s):  
P K Nayak ◽  
A Subramaniam ◽  
S Subramanian ◽  
S Sahu ◽  
C Mondal ◽  
...  
Keyword(s):  
Near Infrared ◽  
Spectral Energy Distribution ◽  
Variable Mass ◽  
Intrinsic Property ◽  
Small Variation ◽  
Magellanic Cloud ◽  
Spectral Energy ◽  
Small Range ◽  
Small Magellanic Cloud ◽  
Red Clump

Abstract We have demonstrated the advantage of combining multi-wavelength observations, from the ultraviolet (UV) to near-infrared, to study Kron 3, a massive star cluster in the Small Magellanic Cloud. We have estimated the radius of the cluster Kron 3 to be 2${_{.}^{\prime}}$0 and for the first time, we report the identification of NUV-bright red clump (RC) stars and the extension of the RC in colour and magnitude in the NUV versus (NUV−optical) colour-magnitude diagram (CMD). We found that extension of the RC is an intrinsic property of the cluster and it is not due to contamination of field stars or differential reddening across the field. We studied the spectral energy distribution of the RC stars, and estimated a small range in temperature ∼5000–5500 K, luminosity ∼60–90 L⊙ and radius ∼8.0–11.0 R⊙ supporting their RC nature. The range of UV magnitudes amongst the RC stars (∼23.3 to 24.8 mag) is likely caused by the combined effects of variable mass loss, variation in initial helium abundance (Yini = 0.23 to 0.28), and a small variation in age (6.5-7.5 Gyr) and metallicity ([Fe/H] = −1.5 to −1.3). Spectroscopic follow-up observations of RC stars in Kron 3 are necessary to confirm the cause of the extended RC.

scholarly journals Comparison of Discrete Sources in Radio and Hα Surveys of the Magellanic Clouds and the Potential for the New Hα Survey

1998 ◽  
Vol 15 (1) ◽  
pp. 128-131 ◽  
Author(s):  
Miroslav D. Filipović ◽  
Paul A. Jones ◽  
Graeme L. White ◽  
Raymond F. Haynes
Keyword(s):  
Supernova Remnants ◽  
Hii Regions ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
Small Magellanic Cloud

AbstractWe present a comparison between the latest Parkes radio surveys (Filipović et al. 1995, 1996, 1997) and Hα surveys of the Magellanic Clouds (Kennicutt & Hodge 1986). We have found 180 discrete sources in common for the Large Magellanic Cloud (LMC) and 40 in the field of the Small Magellanic Cloud (SMC). Most of these sources (95%) are HII regions and supernova remnants (SNRs). A comparison of the radio and Hα flux densities shows a very good correlation and we note that many of the Magellanic Clouds SNRs are embedded in HII regions.

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