scholarly journals Massive star population of the Virgo Cluster galaxy NGC4535

2018 ◽  
Vol 618 ◽  
pp. A185 ◽  
Author(s):  
Z. T. Spetsieri ◽  
A. Z. Bonanos ◽  
M. Kourniotis ◽  
M. Yang ◽  
S. Lianou ◽  
...  
Keyword(s):  
Massive Star ◽  
Absolute Magnitude ◽  
Virgo Cluster ◽  
Star Formation History ◽  
Wide Field ◽  
Absolute Deviation ◽  
Cluster Galaxy ◽  
Solar Metallicity ◽  
Red Supergiants ◽  
Candidate Variable

We analyzed the massive star population of the Virgo Cluster galaxy NGC 4535 using archival Hubble Space Telescope Wide Field Planetary Camera 2 images in filters F555W and F814W, equivalent to Johnson V and Kron-Cousins I. We performed high precision point spread function fitting photometry of 24353 sources including 3762 candidate blue supergiants, 841 candidate yellow supergiants, and 370 candidate red supergiants. We estimated the ratio of blue to red supergiants as a decreasing function of galactocentric radius. Using Modules for Experiments in Stellar Astrophysics (MESA) isochrones at solar metallicity, we defined the luminosity function and estimated the star formation history of the galaxy over the last 60 Myr. We conducted a variability search in the V and I filters using three variability indexes: the median absolute deviation, the interquartile range, and the inverse von-Neumann ratio. This analysis yielded 120 new variable candidates with absolute magnitudes ranging from MV = −4 to −11 mag. We used the MESA evolutionary tracks at solar metallicity to classify the variables based on their absolute magnitude and their position on the color-magnitude diagram. Among the new candidate variable sources are eight candidate variable red supergiants, three candidate variable yellow supergiants and one candidate luminous blue variable, which we suggest for follow-up observations.

scholarly journals The HST Key Project galaxies NGC 1326A, NGC 1425, and NGC 4548: New variable stars and massive star population

2019 ◽  
Vol 629 ◽  
pp. A3 ◽  
Author(s):  
Z. T. Spetsieri ◽  
A. Z. Bonanos ◽  
M. Yang ◽  
M. Kourniotis ◽  
D. Hatzidimitriou
Keyword(s):  
Star Formation ◽  
Massive Star ◽  
Absolute Magnitude ◽  
Variable Stars ◽  
Star Formation History ◽  
Wide Field ◽  
Absolute Deviation ◽  
Solar Metallicity ◽  
Red Supergiants ◽  
Candidate Variable

Studies of the massive star population in galaxies beyond the Local Group are the key to understanding the link between their numbers and modes of star formation in different environments. We present the analysis of the massive star population of the galaxies NGC 1326A, NGC 1425, and NGC 4548 using archival images obtained with the Hubble Space Telescope Wide Field Planetary Camera 2 in the F555W and F814W filters. Through high-precision point spread function fitting photometry for all sources in the three fields, we identified 7640 candidate blue supergiants, 2314 candidate yellow supergiants, and 4270 candidate red supergiants. We provide an estimate of the ratio of blue to red supergiants for each field as a function of galactocentric radius. Using Modules for Experiments in Stellar Astrophysics (MESA) at solar metallicity, we defined the luminosity function and estimated the star formation history of each galaxy. We carried out a variability search in the V and I filters using three variability indexes: the median absolute deviation, the interquartile range, and the inverse von Neumann ratio. This analysis yielded 243 new variable candidates with absolute magnitudes ranging from MV = −4 to −10 mag. We classified the variable stars based on their absolute magnitude and their position on the color–magnitude diagram using the MESA evolutionary tracks at solar metallicity. Our analysis yielded 8 candidate variable blue supergiants, 12 candidate variable yellow supergiants, 21 candidate variable red supergiants, and 4 candidate periodic variables.

scholarly journals Planetary Nebulae and their parent stellar populations. Tracing the mass assembly of M87 and Intracluster light in the Virgo cluster core

2015 ◽  
Vol 11 (S317) ◽  
pp. 69-76
Author(s):  
Magda Arnaboldi ◽  
Alessia Longobardi ◽  
Ortwin Gerhard
Keyword(s):  
Planetary Nebulae ◽  
Major Axis ◽  
Large Magellanic Cloud ◽  
Virgo Cluster ◽  
Star Formation History ◽  
Cluster Core ◽  
Line Of Sight ◽  
Cluster Galaxy ◽  
Mass Assembly ◽  
Intracluster Light

AbstractThe diffuse extended outer regions of galaxies are hard to study because they are faint, with typical surface brightness of 1% of the dark night sky. We can tackle this problem by using resolved star tracers which remain visible at large distances from the galaxy centers. This article describes the use of Planetary Nebulae as tracers and the calibration of their properties as indicators of the star formation history, mean age and metallicity of the parent stars in the Milky Way and Local Group galaxies. We then report on the results from a deep, extended, planetary nebulae survey in a 0.5 deg2region centered on the brightest cluster galaxy NGC 4486 (M87) in the Virgo cluster core, carried out with SuprimeCam@Subaru and FLAMES-GIRAFFE@VLT. Two planetary nebulae populations are identified out to 150 kpc distance from the center of M87. One population is associated with the M87 halo and the second one with the intracluster light in the Virgo cluster core. They have different line-of-sight velocity and spatial distributions, as well as different planetary nebulae specific frequencies and luminosity functions. The intracluster planetary nebulae in the surveyed region correspond to a luminosity of four times the luminosity of the Large Magellanic Cloud. The M87 halo planetary nebulae trace an older, more metal-rich, parent stellar population. A substructure detected in the projected phase-space of the line-of-sight velocity vs. major axis distance for the M87 halo planetary nebulae provides evidence for the recent accretion event of a satellite galaxy with luminosity twice that of M33. The satellite stars were tidally stripped about 1 Gyr ago, and reached apocenter at a major axis distance of 60–90 kpc from the center of M87. The M87 halo is still growing significantly at the distances where the substructure is detected.

scholarly journals The historical record of massive star formation in Cygnus

2020 ◽  
Vol 644 ◽  
pp. A62
Author(s):  
F. Comerón ◽  
A. A. Djupvik ◽  
N. Schneider ◽  
A. Pasquali
Keyword(s):  
Star Formation ◽  
Massive Star ◽  
Historical Record ◽  
Star Formation History ◽  
Visible Range ◽  
Stellar Content ◽  
Massive Star Formation ◽  
The Past ◽  
Red Supergiants ◽  
History Of

Context. The Cygnus region, which dominates the local spiral arm of the Galaxy, is one of the nearest complexes of massive star formation, extending over several hundred parsecs. Its massive stellar content, regions of ongoing star formation, and molecular gas have been studied in detail at virtually all wavelengths. However, little is known of the history of the region beyond the past 10 Myr. Aims. We use the correlations between age, mass and luminosity of red supergiants to explore the history of star formation in Cygnus previous to the formation of the present-day associations. The brightness and spectroscopic characteristics of red supergiants make it easy to identify them and build up a virtually complete sample of such stars at the distance of the Cygnus region, thus providing a record of massive star formation extending several tens of Myr into the past, a period inaccessible through the O and early B stars observable at present. Methods. We have made a selection based on the 2MASS colors of a sample of bright, red stars in an area of 84 square degrees covering the whole present extension of the Cygnus association in the Local Arm. We have obtained spectroscopy in the red visible range allowing an accurate, homogeneous spectral classification as well as a reliable separation between supergiants and other cool stars. Our data are complemented with Gaia Data Release 2 astrometric data. Results. We have identified 29 red supergiants in the area, 17 of which had not been previously classified as supergiants. Twenty-four of the 29 most likely belong to the Cygnus region and four of the remaining to the Perseus arm. We have used their derived luminosities and masses to infer the star formation history of the region. Intense massive star formation activity is found to have started approximately 15 Myr ago, and we find evidence for two other episodes, one taking place between 20 and 30 Myr ago and another one having ended approximately 40 Myr ago. There are small but significant differences between the kinematic properties of red supergiants younger or older then 20 Myr, hinting that stars of the older group were formed outside the precursor of the present Cygnus complex, possibly in the Sagittarius-Carina arm.

scholarly journals Brightest Stars in Galaxies as Distance Indicators

1986 ◽  
Vol 116 ◽  
pp. 31-41 ◽  
Author(s):  
Allan Sandage
Keyword(s):  
Local Group ◽  
Hubble Constant ◽  
Absolute Magnitude ◽  
Virgo Cluster ◽  
Current Status ◽  
Type I ◽  
Red Supergiants ◽  
Absolute Magnitudes ◽  
Distance Indicators ◽  
Eddington Limit

The current status of the absolute magnitude calibration of the brightest blue and red supergiants in galaxies of different absolute magnitudes shows trends of M(star) with M(parent galaxy). Red supergiants show a more shallow correlation than the blue stars for galaxies brighter than MB = −14. For fainter galaxies, the red supergiant method appears to become totally degenerate.Four areas of application of the brightest star data are discussed as (1) determining MB of the Eddington limit to be ∼−10 for blue supergiants, (2) calibration of MB(max) = −20.0±0.4 for type I supernovae, leading to a Hubble constant of HO = 43±10 km s−1 Mpc−1, (3) detection of the deceleration of the cosmological expansion by the Local Group leading to a Local Group mass of 4×1011 M⊙ and a mass-to-blue light ratio of 3, and (4) use of the brightest stars to map the Virgo cluster velocity perturbation of the Hubble flow.

scholarly journals The Fate of Spiral Galaxies in Clusters: The Star Formation History of the Anemic Virgo Cluster Galaxy NGC 4569

2006 ◽  
Vol 651 (2) ◽  
pp. 811-821 ◽  
Author(s):  
A. Boselli ◽  
S. Boissier ◽  
L. Cortese ◽  
A. Gil de Paz ◽  
M. Seibert ◽  
...  
Keyword(s):  
Star Formation ◽  
Spiral Galaxies ◽  
Virgo Cluster ◽  
Star Formation History ◽  
Cluster Galaxy ◽  
Formation History ◽  
History Of

scholarly journals Red Supergiants as Cosmic Abundance Probes: Massive Star Clusters in M83 and the Mass–Metallicity Relation of Nearby Galaxies

2017 ◽  
Vol 847 (2) ◽  
pp. 112 ◽  
Author(s):  
Ben Davies ◽  
Rolf-Peter Kudritzki ◽  
Carmela Lardo ◽  
Maria Bergemann ◽  
Emma Beasor ◽  
...  
Keyword(s):  
Massive Star ◽  
Star Clusters ◽  
Cosmic Abundance ◽  
Red Supergiants ◽  
Nearby Galaxies

scholarly journals Hot halo gas in the Virgo cluster galaxy NGC 4569

2001 ◽  
Vol 380 (1) ◽  
pp. 40-54 ◽  
Author(s):  
D. Tschöke ◽  
D. J. Bomans ◽  
G. Hensler ◽  
N. Junkes
Keyword(s):  
Virgo Cluster ◽  
Cluster Galaxy ◽  
Halo Gas

scholarly journals The progenitors of core-collapse supernovae

2016 ◽  
Vol 12 (S329) ◽  
pp. 32-38
Author(s):  
Morgan Fraser
Keyword(s):  
Black Hole ◽  
Binary Systems ◽  
Massive Star ◽  
Core Collapse ◽  
Red Supergiants ◽  
To Come

AbstractLinking core-collapse SNe to their stellar progenitors is a major ongoing challenge. To date, H rich Type IIP SNe have been shown to come from red supergiants, while there is increasing evidence that the majority of stripped envelope SNe come from binary systems. The first candidates for failed SNe, where a massive star collapses to form a black hole without a bright optical display have been identified, while the range of outbursts and eruptions from pre-SN stars are just beginning to be revealed.

scholarly journals Recovering the Star Formation History of IC1613 Dwarf Galaxy Using Evolved Stars

2018 ◽  
Vol 14 (S344) ◽  
pp. 77-80
Author(s):  
Seyed Azim Hashemi ◽  
Atefeh Javadi ◽  
Jacco Th. van Loon
Keyword(s):  
Star Formation ◽  
Dwarf Galaxy ◽  
Stellar Populations ◽  
Asymptotic Giant Branch ◽  
Star Formation History ◽  
Evolved Stars ◽  
Formation History ◽  
The Galaxy ◽  
Red Supergiants ◽  
Period Variable

AbstractDetermining the star formation history (SFH) is key to understand the formation and evolution of dwarf galaxies. Recovering the SFH in resolved galaxies is mostly based on deep colour–magnitude diagrams (CMDs), which trace the signatures of multiple evolutionary stages of their stellar populations. In distant and unresolved galaxies, the integrated light of the galaxy can be decomposed, albeit made difficult by an age–metallicity degeneracy. Another solution to determine the SFH of resolved galaxies is based on evolved stars; these luminous stars are the most accessible tracers of the underlying stellar populations and can trace the entire SFH. Here we present a novel method based on long period variable (LPV) evolved asymptotic giant branch (AGB) stars and red supergiants (RSGs). We applied this method to reconstruct the SFH for IC1613, an irregular dwarf galaxy at a distance of 750 kpc. Our results provide an independent confirmation that no major episode of star formation occurred in IC1613 over the past 5 Gyr.

scholarly journals 33. Commission de la Statistique Stellaire

1936 ◽  
Vol 5 ◽  
pp. 228-232
Author(s):  
M. Lindblad ◽  
MM. Bok ◽  
Eddington ◽  
Hertzsprung ◽  
S. Hirayama ◽  
...  
Keyword(s):  
White Dwarfs ◽  
Main Sequence ◽  
Spectral Characteristics ◽  
Absolute Magnitude ◽  
Wide Field ◽  
Continuous Absorption ◽  
Trigonometric Parallaxes ◽  
The One ◽  
Almost All ◽  
Made In

In the wide field of research covered by the Commission considerable progress has been made in recent years, and it is only possible here to touch briefly on the results of a few lines of investigation, without any attempt to completeness.Stellar luminosities. On the basis of the new list of Mount Wilson spectroscopic parallaxes and a compilation of the long series of modern trigonometric parallaxes A. van Maanen finds 617 objects within a distance of 20 parsecs from the sun. It is very doubtful, however, if we know all the stars even in the region of 5 parsecs radius. Almost all the known stars within 20 parsecs belong to the main sequence, the faintest star being of absolute magnitude +16.6. The most interesting deviations from the main sequence are the three “white dwarfs”, Сотр. of Sirius, Comp. o2 Eridani, and van Maanen’s F type star. G. P. Kuiper lists 3 additional white dwarfs at larger distances which were estimated to be of types Bo, B7 and A2. For the first two stars, A.C. 70°8247 and Wolf 1346, a revision of the spectral types by Adams and Humason gives A2 and A5, respectively, although the spectra differ considerably from normal ones. The A2 star in Kuiper’s list is the one discovered by Oosterhoff in the region of the cluster h, X Persei; its spectral characteristics have been examined by Öhman and by Humason. The absence of the high-numbered members of the Bahner series and of the continuous absorption at the Balmer limit seems to be an important criterion of such stars. A white dwarf of quite peculiar spectrum (type probably about B8) is the companion of o Ceti discovered spectro-graphically by Joy in 1922. There appear several additional deviations towards faint magnitudes from the main sequence which may be classed more or less safely among the white dwarfs. A few such cases have been discussed at Lund by J. Tuominen.

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