Milky Way metallicity gradient from <i>Gaia</i> DR2 F/1O double-mode Cepheids

Lemasle, B.; Hajdu, G.; Kovtyukh, V. V.; Inno, L.; Grebel, E. K.; Catelan, M.; Bono, G.; François, P.; Kniazev, A. Y.; Silva, R. da; Storm, J.

doi:10.1051/0004-6361/201834050

Cited by 33 publications

(25 citation statements)

References 75 publications

(97 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To further identify high-mass star forming clumps, we have also investigated the presence of methanol Class ii masers as identified by the Methanol MultiBeam survey (MMB; Green et al 2012), which are thought to be exclusively associated with objects in the early phases of high-mass star formation (Urquhart et al 2015). In the whole area of our survey, only 2 methanol Class ii masers are found (G254.880+0.451 and G259.939-0.041), indicating either a lower rate of high-mass star formation, or being the result of the lower metallicity towards the outer Galaxy (Lemasle et al 2018), and thus reducing the available amount of methanol CH 3 OH, which contains two metal atoms.…”

Section: Independent High-mass Star Formation Tracersmentioning

confidence: 82%

A new search for star forming regions in the southern outer Galaxy

König

Urquhart

Wyrowski

et al. 2021

A&A

View full text Add to dashboard Cite

Context. Star formation in the outer Galaxy is thought to be different from that in the inner Galaxy, as it is subject to different environmental parameters such as metallicity, interstellar radiation field, or mass surface density, which all change with galactocentric radius. Extending our star formation knowledge, from the inner to the outer Galaxy, helps us to understand the influences of the change of the environment on star formation throughout the Milky Way. Aims. We aim to obtain a more detailed view on the structure of the outer Galaxy, determining physical properties for a large number of star forming clumps and understanding star formation outside the solar circle. As one of the largest expanding Galactic super-shells is present in the observed region, a unique opportunity is taken here to investigate the influence of such an expanding structure on star formation as well. Methods. We used pointed 12CO(2–1) observations conducted with the APEX telescope to determine the velocity components towards 830 dust clumps identified from 250 μm Herschel/Hi-GAL SPIRE emission maps in the outer Galaxy between 225° < ℓ < 260°. We determined kinematic distances from the velocity components, in order to analyze the structure of the outer Galaxy and to estimate physical properties such as dust temperatures, bolometric luminosities, clump masses, and H2 column densities for 611 clumps. For this, we determined the dust spectral energy density distributions from archival mid-infrared to submillimeter (submm) emission maps. Results. We find the identified CO clouds to be strongly correlated with the highest column density parts of the H I emission distribution, spanning a web of bridges, spurs, and blobs of star forming regions between the larger complexes, unveiling the complex three-dimensional structure of the outer Galaxy in unprecedented detail. Using the physical properties of the clumps, we find an upper limit of 6% (40 sources) capable of forming high-mass stars. This is supported by the fact that only two methanol Class II masers, or 34 known or candidate H II regions, are found in the whole survey area, indicating an even lower fraction that are able to form high-mass stars in the outer Galaxy. We fail to find any correlation of the physical parameters of the identified (potential) star forming regions with the expanding supershell, indicating that although the shell organizes the interstellar material into clumps, the properties of the latter are unaffected. Conclusions. Using the APEX telescope in combination with publicly available Hi-GAL, MSX, and Wise continuum emission maps, we were able to investigate the structure and properties of a region of the Milky Way in unprecedented detail.

show abstract

Section: Independent High-mass Star Formation Tracersmentioning

confidence: 82%

A new search for star forming regions in the southern outer Galaxy

König

Urquhart

Wyrowski

et al. 2021

A&A

View full text Add to dashboard Cite

show abstract

“…Hence, to combine the FU and FO Cepheids together in a single P-L diagram, one requires to first convert period of FO Cepheids into the corresponding period of FU Cepheids which requires a well defined relation connecting the two periods. As vast majority of Cepheids pulsates only in a single mode, there are only a limited number of Cepheids which pulsate in two modes simultaneously (Lemasle et al 2018). Using the high resolution spectroscopic observations of 17 such double mode Galactic Cepheids, Sziládi et al (2007) derived a relation for transformation of FO and FU periods as following:…”

Section: Methodology Of Reddening Determinationmentioning

confidence: 99%

Reddening map and recent star formation in the Magellanic Clouds based on OGLE IV Cepheids

Joshi

Panchal

2019

A&A

View full text Add to dashboard Cite

Context. The reddening maps of the Large Magellanic Cloud (LMC) and Small Magellanic Cloud (SMC) are constructed using the Cepheid Period-Luminosity (P-L) relations. Aims. We examine reddening distribution across the LMC and SMC through largest data on Classical Cepheids provided by the OGLE Phase IV survey. We also investigate the age and spatio-temporal distributions of Cepheids to understand the recent star formation history in the LMC and SMC. Methods. The V and I band photometric data of 2476 fundamental mode (FU) and 1775 first overtone mode (FO) Cepheids in the LMC and 2753 FU and 1793 FO Cepheids in the SMC are analyzed for their P-L relations. We convert period of FO Cepheids to corresponding period of FU Cepheids before combining the two modes of Cepheids. Both galaxies are divided into small segments and combined FU and FO P-L diagrams are drawn in two bands for each segment. The reddening analysis is performed on 133 segments covering a total area of about 154.6 deg 2 in the LMC and 136 segments covering a total area of about 31.3 deg 2 in the SMC. By comparing with well calibrated P-L relations of these two galaxies, we determine reddening E(V − I) in each segment and equivalent reddening E(B − V) assuming the normal extinction law. The period-age relations are used to derive the age of the Cepheids.Results. Using reddening values in different segments across the LMC and SMC, reddening maps are constructed. We find clumpy structures in the reddening distributions of the LMC and SMC. From the reddening map of the LMC, highest reddening of E(V − I) = 0.466 mag is traced in the region centered at α ∼ 85 o .13, δ ∼ −69 o .34 which is in close vicinity of the star forming HII region 30 Doradus. In the SMC, maximum reddening of E(V − I) = 0.189 mag is detected in the region centered at α ∼ 12 o .10, δ ∼ −73 o .07. The mean reddening values in the LMC and SMC are estimated as E(V − I) LMC = 0.113 ± 0.060 mag, E(B − V) LMC = 0.091 ± 0.050 mag, E(V − I) S MC = 0.049 ± 0.070 mag, and E(B − V) S MC = 0.038 ± 0.053 mag.Conclusions. The LMC reddening map displays heterogeneous distribution having small reddening in the central region and higher reddening towards eastern side of the LMC bar. The SMC have relatively small reddening in peripheral regions but larger reddening towards south-west region. In these galaxies, we see an evidence of a common enhanced Cepheid population at around 200 Myr ago which appears to have occurred due to close encounter between the two clouds.

show abstract

“…In several of these cases, when sufficient data were available, we used the Gaia photometry to recalculate the periods using the literature values as a starting point and refining these values using Period04 package (Lenz & Breger 2005). In this context, particularly useful was the work by Lemasle et al (2018), who analysed in detail the multimode DCEPs in DR2, providing a list of reliable new multimode candidates.…”

Section: Detailed Reclassificationmentioning

confidence: 99%

Reclassification of Cepheids in the Gaia Data Release 2

Ripepi

Molinaro²,

Musella³

et al. 2019

A&A

122

128

View full text Add to dashboard Cite

Context. Classical Cepheids are the most important primary indicators for the extragalactic distance scale. Establishing the precise zero points of their period-luminosity and period-Wesenheit (PL/PW) relations has profound consequences on the estimate of H 0 . Type II Cepheids are also important distance indicators and tracers of old stellar populations. Aims. The recent Data Release 2 (DR2) of the Gaia spacecraft includes photometry and parallaxes for thousands of classical and Type II Cepheids. We seek to review the classification of Gaia DR2 Cepheids and to derive precise PL/PW for the Magellanic Clouds (MCs) and Galactic Cepheids. Methods. We adopted information from the literature and the Gaia astrometry and photometry to assign DR2 Galactic Cepheids to the classical, anomalous, and Type II Cepheids classes. Results. We reclassified the DR2 Galactic Cepheids and derived new precise PL/PW relations in the Gaia passbands for the MCs and Milky Way Cepheids. We investigated for the first time the dependence on metallicity of the PW relation for classical Cepheids in the Gaia bands, finding inconclusive results. Conclusions. According to our analysis, the zero point of the Gaia DR2 parallaxes as estimated from classical and Type II Cepheids seems likely to be underestimated by ∼0.07 mas, which agrees with recent literature. The next Gaia data releases are expected to fix this zero point offset to allow eventually a determination of H 0 to less than 1%.Article published by EDP Sciences A14, page 1 of 17 A&A 625, A14 (2019)

show abstract

Milky Way metallicity gradient from Gaia DR2 F/1O double-mode Cepheids

Cited by 33 publications

References 75 publications

A new search for star forming regions in the southern outer Galaxy

A new search for star forming regions in the southern outer Galaxy

Reddening map and recent star formation in the Magellanic Clouds based on OGLE IV Cepheids

Reclassification of Cepheids in the Gaia Data Release 2

Contact Info

Product

Resources

About