The Properties of the Magellanic Bridge Based on OGLE IV RR Lyrae Variables

Wagner-Kaiser, R.; Sarajedini, Ata

doi:10.1093/mnras/stw3206

Cited by 12 publications

(11 citation statements)

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“…Despite later studies (Nidever et al 2011;Bagheri et al 2013;Skowron et al 2014;Noël et al 2013Noël et al , 2015Jacyszyn-Dobrzeniecka et al 2017) uncovering the presence of intermediate-age/old stellar populations in the central and western regions of the MB, the interpretations as to their origin differed. While Noël et al (2013Noël et al ( , 2015 and Carrera et al (2017) supported a tidal origin for these intermediateage stars in the MB, Jacyszyn-Dobrzeniecka et al (2017) and Wagner-Kaiser & Sarajedini (2017) suggested them as part of the overlapping stellar halos of the MCs. Belokurov et al (2017) reported the existence of a stellar tidal bridge from the study of RR Lyrae stars in the Gaia data release 1 (DR1) (Gaia Collaboration et al 2016) and found that this old stellar bridge is not aligned with the gaseous MB but is shifted by ∼ 5 • from the bridge traced by young main sequence stars (the latter is well aligned with the gaseous bridge).…”

Section: Introductionmentioning

confidence: 94%

Gaia view of a stellar sub-structure in front of the Small Magellanic Cloud

Omkumar

Subramanian

Niederhofer

et al. 2020

Monthly Notices of the Royal Astronomical Society

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Recent observational studies identified a foreground stellar sub-structure traced by red clump (RC) stars (∼ 12 kpc in front of the main body) in the eastern regions of the Small Magellanic Cloud (SMC) and suggested that it formed during the formation of the Magellanic Bridge (MB), due to the tidal interaction of the Magellanic Clouds. Previous studies investigated this feature only up to 4$\rlap{.}^{\circ }$0 from the centre of the SMC due to the limited spatial coverage of the data and hence could not find a physical connection with the MB. To determine the spatial extent and properties of this foreground population, we analysed data from the Gaia data release 2 (DR2) of a ∼314 deg2 region centred on the SMC, which cover the entire SMC and a significant portion of the MB. We find that the foreground population is present only between 2$\rlap{.}^{\circ }$5 to ∼ 5○–6○ from the centre of the SMC in the eastern regions, towards the MB and hence does not fully overlap with the MB in the plane of the sky. The foreground stellar population is found to be kinematically distinct from the stellar population of the main body with ∼ 35 km s−1 slower tangential velocity and moving to the North-West relative to the main body. Though the observed properties are not fully consistent with the simulations, a comparison indicates that the foreground stellar structure is most likely a tidally stripped counterpart of the gaseous MB and might have formed from the inner disc (dominated by stars) of the SMC. A chemical and 3D kinematic study of the RC stars along with improved simulations, including both tidal and hydro-dynamical effects, are required to understand the offset between the foreground structure and MB.

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Section: Introductionmentioning

confidence: 94%

Gaia view of a stellar sub-structure in front of the Small Magellanic Cloud

Omkumar

Subramanian

Niederhofer

et al. 2020

Monthly Notices of the Royal Astronomical Society

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“…These radially pulsating variables are valuable tracers of old and metal-poor stellar populations and provide extragalactic distance estimates with well-defined period-luminosity relations (PLRs), especially in the near-infrared bands (Longmore et al 1986;Bono et al 2001;Catelan et al 2004;Sollima et al 2006;Muraveva et al 2015;Braga et al 2015;Neeley et al 2015). Additionally, a narrow range of the intrinsic colors of RR Lyrae stars also serves as a useful reddening indicator (Sturch 1966; Ma-E-mail:susmitadas130@gmail.com teo et al 1995;Guldenschuh et al 2005;Wagner-Kaiser & Sarajedini 2017). RR Lyrae and Cepheid variables are both excellent probes for the understanding of the theory of stellar pulsation and evolution.…”

Section: Introductionmentioning

confidence: 99%

On the variation of light-curve parameters of RR Lyrae variables at multiple wavelengths

Das

Bhardwaj

Singh

et al. 2018

Monthly Notices of the Royal Astronomical Society

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We present a detailed light curve analysis of RR Lyrae variables at multiple wavelengths using Fourier decomposition method. The time-series data for RR Lyrae variables in the Galactic bulge and the Magellanic Clouds are taken from the Optical Gravitational Lensing Experiment survey while the infrared light curves are compiled from the literature. We also analyse the multiband theoretical light curves that are generated from the stellar pulsation models of RR Lyrae stars for a wide range of metal-abundances. We find that the theoretical light curve parameters with different metal abundances are consistent with observed parameters in most period bins at both optical and infrared wavelengths. The theoretical and observed Fourier amplitude parameters decrease with increase in wavelength while the Fourier phase parameters increase with wavelength at a given period. We use absolute magnitudes for a subset of theoretical models that fit the observed optical RR Lyrae light curves in the Large Magellanic Cloud to estimate a distance modulus, µ LMC = 18.51 ± 0.07, independent of the metallicity. We also use Fourier analysis to study the period-color and amplitude-color relations for RR Lyrae stars in the Magellanic Clouds using optical data and find that the slope of period-color relation at minimum light is very shallow or flat and becomes increasingly significant at the maximum light for RRab stars. We also find that the metallicity dependence of the periodcolor relations increases as we go from minimum to maximum light, suggesting that the mean light results are indeed an average of the various pulsational phases. We summarize that the average variation in these relations is consistent between theory and observations and supports the theory of the interaction of the stellar photosphere and the hydrogen ionization front.

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“…Though several studies (Nidever et al 2011;Bagheri, Cioni & Napiwotzki 2013;Noël et al 2013;Skowron et al 2014;Noël et al 2015;Belokurov et al 2017;Jacyszyn-Dobrzeniecka et al 2017Massana et al 2020) found intermediate-age/old (age > 2 Gyr) stars around the MB region, the interpretations of their origin differed. While Noël et al (2013Noël et al ( , 2015 and Carrera et al (2017) supported a tidal origin for these intermediate-age stars, Jacyszyn-Dobrzeniecka et al (2017) and Wagner-Kaiser & Sarajedini (2017) suggested them as part of the overlapping stellar halos of the MCs. No conclusive evidence of a stellar counterpart (consisting of stars older than 1.5 Gyr) to the MS has been found so far.…”

Section: Introductionmentioning

confidence: 92%

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

James,

Subramanian,

Omkumar

et al. 2021

Preprint

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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 substructure 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.

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The Properties of the Magellanic Bridge Based on OGLE IV RR Lyrae Variables

Cited by 12 publications

References 50 publications

Gaia view of a stellar sub-structure in front of the Small Magellanic Cloud

Gaia view of a stellar sub-structure in front of the Small Magellanic Cloud

On the variation of light-curve parameters of RR Lyrae variables at multiple wavelengths

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

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