Monitoring survey of pulsating giant stars in the Local Group galaxies: survey description, science goals, target selection

Saremi, Elham; Javadi, Atefeh; Loon, Jacco Th. van; Khosroshahi, Habib G.; Abedi, Abbas; Bamber, James R.; Hashemi, Seyed Azim; Nikzat, F.; Nezhad, A Molaei

doi:10.1088/1742-6596/869/1/012068

Cited by 11 publications

(11 citation statements)

References 9 publications

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“…The data set was obtained with WFC/INT over a period of 3 yr (2015 June to 2017 October) from a survey of the majority of dwarf galaxies in the Local Group, including 43 dSph, 6 dIrr, 6 dTrans, and 4 globular clusters, all visible in the northern hemisphere (Saremi et al 2017(Saremi et al , 2020. The WFC is an optical mosaic camera at the prime focus of the 2.5 m Isaac Newton Telescope (INT) in La Palma, Spain.…”

Section: Observationsmentioning

confidence: 99%

The Isaac Newton Telescope Monitoring Survey of Local Group Dwarf Galaxies. IV. The Star Formation History of Andromeda VII Derived from Long-period Variable Stars

Navabi

Saremi²,

Javadi³

et al. 2021

ApJ

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We have examined the star formation history (SFH) of Andromeda VII (And VII), the brightest and most massive dwarf spheroidal (dSph) satellite of the Andromeda galaxy (M31). Although M31 is surrounded by several dSph companions with old stellar populations and low metallicity, it has a metal-rich stellar halo with an age of 6-8 Gyr. This indicates that any evolutionary association between the stellar halo of M31 and its dSph system is frail. Therefore, the question is whether And VII (a high-metallicity dSph located ∼220 kpc from M31) can be associated with M31ʼs young, metal-rich halo. Here we perform the first reconstruction of the SFH of And VII employing long-period variable (LPV) stars. As the most evolved asymptotic giant branch and red supergiant stars, the birth mass of LPVs can be determined by connecting their near-infrared photometry to theoretical evolutionary tracks. We found 55 LPV candidates within two half-light radii, using multiepoch imaging with the Isaac Newton Telescope in the i and V bands. Based on their birth mass function, the star formation rate (SFR) of And VII was obtained as a function of cosmic time. The main epoch of star formation occurred ; 6.2 Gyr ago with an SFR of 0.006 ± 0.002 M e yr −1 . Over the past 6 Gyr, we find slow star formation, which continued until 500 Myr ago with an SFR ∼ 0.0005 ± 0.0002 M e yr −1 . We determined And VII's stellar mass M = (13.3 ± 5.3) × 10 6 M e within a half-light radius = ¢  ¢ r 3.8 0.3 1 2 and metallicity Z = 0.0007, and we also derived its distance modulus of μ = 24.38 mag.

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Section: Observationsmentioning

confidence: 99%

The Isaac Newton Telescope Monitoring Survey of Local Group Dwarf Galaxies. IV. The Star Formation History of Andromeda VII Derived from Long-period Variable Stars

Navabi

Saremi²,

Javadi³

et al. 2021

ApJ

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“…Over a period of three years (2015 June to 2018 February), we used the Wide Field Camera (WFC) to survey the majority of dwarf galaxies in the LG (Saremi et al 2017). The WFC is an optical mosaic camera at the 2.5 m INT of the Observatorio del Roque de los Muchachos (La Palma).…”

Section: Survey Design and Observationsmentioning

confidence: 99%

The Isaac Newton Telescope Monitoring Survey of Local Group Dwarf Galaxies. I. Survey Overview and First Results for Andromeda I

Saremi

Javadi

Loon

et al. 2020

ApJ

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An optical monitoring survey in nearby dwarf galaxies was carried out with the 2.5 m Isaac Newton Telescope. Fifty-five dwarf galaxies and four isolated globular clusters in the Local Group were observed with the Wide Field Camera. The main aims of this survey are to identify the most evolved asymptotic giant branch (AGB) stars and red supergiants at the end-point of their evolution based on their pulsational instability, use their distribution over luminosity to reconstruct the star formation history, quantify the dust production and mass loss from modeling the multiwavelength spectral energy distributions (SEDs), and relate this to luminosity and radius variations. In this first of a series of papers, we present the methodology of the variability survey and describe the photometric catalog of the Andromeda I (And I) dwarf galaxy as an example of the survey, and we discuss the identified long period variable (LPV) stars. We detected 5581 stars and identified 59 LPV candidates within two half-light radii of the center of And I. The amplitudes of these candidates range from 0.2 to 3 mag in the i-band. Seventy-five percent of detected sources and 98% of LPV candidates are detected at mid-infrared wavelengths. We show evidence for the presence of dust-producing AGB stars in this galaxy including five extreme AGB (x-AGB) stars, and we model some of their SEDs. A distance modulus of 24.41 mag for And I was determined based on the tip of the red giant branch. Also, a half-light radius of 3 2±0 3 was calculated. Unified AstronomyThesaurus concepts: Asymptotic giant branch stars (2100); Local Group (929); Stellar mass loss (1613); Stellar evolution (1599); Luminosity function (942); Stellar mass functions (1612); Stellar oscillations (1617); Galaxy stellar content (621); Dwarf galaxies (416); Surveys (1671); Long period variable stars (935); Galaxy distances (590)

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“…Meanwhile, the most desirable models to satisfy our purpose are those theoretical models from the Padova group (Marigo et al, 2017). Investigating the SFR and the used method were explained thoroughly in Hamedani Golshan et al (2017), Hashemi et al (2017), Javadi et al (2011, Rezaei Kh et al (2014), Saremi et al (2017Saremi et al ( , 2019Saremi et al ( , 2020.…”

Section: Methodsmentioning

confidence: 99%

From Evolved Stars to the Formation and Evolution of NGC 6822

Taefi

Saremi

Javadi

2020

ComBAO

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NGC6822, an isolated dwarf irregular galaxy (dIrr), due to close distance, apparent isolation, and easy observation, has been always selected as a desired candidate for studying star formation and galactic evolution, without the strong gravitational influences of other systems. To derive the SFH of NGC6822, the method mentioned by Javadi et al. (2011) is used which is based on theoretical models coupled with color-magnitude diagrams (CMDs) by using directly the long period variable (LPV) stars which are mostly asymptotic giant branch (AGB) stars at their very late stage of evolution, as well as more massive red super-giant (RSG) stars according to their significant role to study the star formation rate (SFR). To calculate the SFH in the bar of the galaxy, we use more than 600 LPV stars from different catalogs of variable stars that two of the most important are Whitelock et al. (2013) and Letarte et al. (2002) that they reported the main part of the LPVs and the Carbon stars, respectively, Patrick et al. (2015) announced the RSG stars. Understanding the star formation history of NGC 6822 plays an important role in comparing the galaxy history evolution with other nearby dwarf galaxies as well as studying the nature of the evolving population of galaxies which were detected in deep redshift surveys.

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Monitoring survey of pulsating giant stars in the Local Group galaxies: survey description, science goals, target selection

Cited by 11 publications

References 9 publications

The Isaac Newton Telescope Monitoring Survey of Local Group Dwarf Galaxies. IV. The Star Formation History of Andromeda VII Derived from Long-period Variable Stars

The Isaac Newton Telescope Monitoring Survey of Local Group Dwarf Galaxies. IV. The Star Formation History of Andromeda VII Derived from Long-period Variable Stars

The Isaac Newton Telescope Monitoring Survey of Local Group Dwarf Galaxies. I. Survey Overview and First Results for Andromeda I

From Evolved Stars to the Formation and Evolution of NGC 6822

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