scholarly journals Detection and measurement of expanding ionized shells around young star clusters

2015 ◽  
Vol 11 (S315) ◽  
Author(s):  
John Beckman ◽  
Artemi Camps Fariña ◽  
Javier Zaragoza Cardiel ◽  
Joan Font
Keyword(s):  
Supernova Remnants ◽  
Spatial Scales ◽  
Young Star ◽  
Data Cube ◽  
Physical Parameters ◽  
Integral Field Spectroscopy ◽  
Hα Emission ◽  
Nearby Galaxies ◽  
Expanding Shells ◽  
Young Star Clusters

AbstractWe present a new method (BUBBLY) for detecting expanding components of ionized gas using integral field spectroscopy, showing its capabilities not only in detecting but also in obtaining the key physical parameters of the expanding shells: their expansion velocities and masses. The main advantages are that the detection is performed automatically via software and that we can derive most parameters of the shells, so it is suitable for detailed studies of feedback in nearby galaxies. The software can easily be configured to run on any data cube mapping an emission line over a spatial field. We also present results obtained by running BUBBLY on observations of Hα emission with the Fabry-Perot spectrograph GHαFaS: two sets of spectacular results at widely different spatial scales: the Antennae galaxies show multiple giant bubbles of size ~300pc around the brightest clusters, while inside a region in M33 we find three nested supernova remnants, with which we can study the feedback on the molecular gas surrounding the cluster.

scholarly journals The VLT-FLAMES Tarantula Survey

2019 ◽  
Vol 624 ◽  
pp. A128 ◽  
Author(s):  
N. Britavskiy ◽  
D. J. Lennon ◽  
L. R. Patrick ◽  
C. J. Evans ◽  
A. Herrero ◽  
...  
Keyword(s):  
Near Infrared ◽  
Interstellar Extinction ◽  
Large Magellanic Cloud ◽  
Young Star ◽  
Physical Parameters ◽  
Single Star ◽  
Near Ir ◽  
Large Spread ◽  
Red Supergiants ◽  
Young Star Clusters

Aims. We estimate physical parameters for the late-type massive stars observed as part of the VLT-FLAMES Tarantula Survey (VFTS) in the 30 Doradus region of the Large Magellanic Cloud (LMC). Methods. The observational sample comprises 20 candidate red supergiants (RSGs) which are the reddest ((B − V) > 1 mag) and brightest (V < 16 mag) objects in the VFTS. We use optical and near-infrared (near-IR) photometry to estimate their temperatures and luminosities, and introduce the luminosity–age diagram to estimate their ages. Results. We derive physical parameters for our targets, including temperatures from a new calibration of (J − Ks)0 colour for luminous cool stars in the LMC, luminosities from their J-band magnitudes (thence radii), and ages from comparisons with current evolutionary models. We show that interstellar extinction is a significant factor for our targets, highlighting the need to take it into account in the analysis of the physical parameters of RSGs. We find that some of the candidate RSGs could be massive AGB stars. The apparent ages of the RSGs in the Hodge 301 and SL 639 clusters show a significant spread (12–24 Myr). We also apply our approach to the RSG population of the relatively nearby NGC 2100 cluster, finding a similarly large spread. Conclusions. We argue that the effects of mass transfer in binaries may lead to more massive and luminous RSGs (which we call “red stragglers”) than expected from single-star evolution, and that the true cluster ages correspond to the upper limit of the estimated RSG ages. In this way, the RSGs can serve as a new and potentially reliable age tracer in young star clusters. The corresponding analysis yields ages of 24−3+5 Myr for Hodge 301, 22−5+6 Myr for SL 639, and 23−2+4 Myr for NGC 2100.

scholarly journals The Mass Function of Young Star Clusters in our Galaxy and Nearby Galaxies: Is It Universal?

2002 ◽  
Vol 207 ◽  
pp. 515-524
Author(s):  
Ram Sagar
Keyword(s):  
Star Clusters ◽  
Dynamical Evolution ◽  
Mass Function ◽  
Young Star ◽  
Initial Mass Function ◽  
Galactocentric Distance ◽  
Photometric Observations ◽  
Nearby Galaxies ◽  
Mass Segregation ◽  
Young Star Clusters

Mass functions (MFs) derived from photometric observations of young star clusters of our Galaxy, the Magellanic Clouds (MCs), M31 and M33 have been used to investigate the question of universality of the initial mass function and presence of mass segregation in these systems. Observational determination of the MF slope of young star clusters have an inherent uncertainty of at least ∼ 1.0 dex in the Milky Way and of ∼ 0.4 dex in the MCs. There is no obvious dependence of the MF slope on either galactocentric distance or age of the young star clusters or on the spatial concentration of the stars formed or on the galactic characteristics including metallicity. Effects of mass segregation have been observed in a good number of young stellar groups of our Galaxy and MCs. As their ages are much smaller than their dynamical evolution times, star formation processes seem to be responsible for the observed mass segregation in them.

scholarly journals Star Formation in NGC 4038/4039

2001 ◽  
Vol 205 ◽  
pp. 206-207
Author(s):  
Sabine Mengel ◽  
Niranjan Thatte ◽  
Matthew Lehnert ◽  
Reinhard Genzel
Keyword(s):  
Star Formation ◽  
Near Infrared ◽  
Spatial Scales ◽  
Star Clusters ◽  
Young Star ◽  
Bolometric Luminosity ◽  
Integral Field Spectroscopy ◽  
Show Evidence ◽  
Northwestern Region ◽  
Age Range

We performed near infrared integral field spectroscopy of several star clusters and the nuclei of the prototypical merger NGC 4038/39 (“The Antennae”). Near infrared (NIR) images covered both galaxies. The collision of the two gas-rich spiral galaxies has triggered a starburst obvious from a large number of young star clusters. ISO data suggest that the most active star formation occurs in the region where the two galaxy disks overlap. A significant fraction of the total bolometric luminosity of the system is produced there. Since this region is heavily extincted in the optical, the investigation was made in the NIR. Using Brγ emission and CO absorption features as age indicators, we derive the ages and mass estimates of the star clusters from a comparison with stellar synthesis models. Extinction is calculated from the Brγ/Hα ratio. The young, bright star clusters have ages ranging from 4-12 Myrs, while the nuclear starbursts are much older (50-80 Myrs). The overlap region hosts most of the youngest star clusters below ∼8 Myrs, while the northwestern region is dominated by star clusters in the age range between 8 and 12 Myrs. Several regions, including the northern nucleus, show evidence for sequential star formation on small spatial scales (< 100pc).

scholarly journals Propagation of star formation at sub-kiloparsec scales

2019 ◽  
Vol 488 (3) ◽  
pp. 3045-3054
Author(s):  
A S Gusev ◽  
E V Shimanovskaya
Keyword(s):  
Star Formation ◽  
Spatial Scales ◽  
Dominant Role ◽  
Star Clusters ◽  
Young Star ◽  
H Ii Regions ◽  
Supernova Explosions ◽  
Stellar Associations ◽  
Young Star Clusters

ABSTRACT We study the propagation of star formation based on the investigation of the separation of young star clusters from H ii regions nearest to them. The relation between the separation and U − B colour index (or age) of a star cluster was found. The average age of star clusters increases with the separation as the 1.0–1.2 power in the separation range from 40 to 200 pc and as the 0.4–0.9 power in the range of 100–500 pc in the galaxies with symmetric morphology. The galaxies with distorted asymmetric disc structure show more complex and steeper (power >1.2 at separations from 40 to 500 pc) dependence between the age and the separation. Our results confirm the findings of previous studies on the dominant role of turbulence in propagation of the star formation process on spatial scales up to 500 pc and on time-scales up to 300 Myr. On a smaller scale (≤100 pc), other physical processes, such as stellar winds and supernova explosions, play an important role along with turbulence. On the scale of stellar associations (100–200 pc and smaller), the velocity of star formation propagation is almost constant and it has a typical value of a few km s−1.

Application of Remote Sensing in Agriculture

2014 ◽  
Vol 13 (1) ◽  
Author(s):  
Jan Piekarczyk
Keyword(s):  
Remote Sensing ◽  
Precision Agriculture ◽  
Crop Production ◽  
Satellite Images ◽  
Crop Yields ◽  
Spatial Scales ◽  
Strong Relationship ◽  
Physical Parameters ◽  
Agricultural Crop ◽  
Remote Sensing Methods

AbstractWith increasing intensity of agricultural crop production increases the need to obtain information about environmental conditions in which this production takes place. Remote sensing methods, including satellite images, airborne photographs and ground-based spectral measurements can greatly simplify the monitoring of crop development and decision-making to optimize inputs on agricultural production and reduce its harmful effects on the environment. One of the earliest uses of remote sensing in agriculture is crop identification and their acreage estimation. Satellite data acquired for this purpose are necessary to ensure food security and the proper functioning of agricultural markets at national and global scales. Due to strong relationship between plant bio-physical parameters and the amount of electromagnetic radiation reflected (in certain ranges of the spectrum) from plants and then registered by sensors it is possible to predict crop yields. Other applications of remote sensing are intensively developed in the framework of so-called precision agriculture, in small spatial scales including individual fields. Data from ground-based measurements as well as from airborne or satellite images are used to develop yield and soil maps which can be used to determine the doses of irrigation and fertilization and to take decisions on the use of pesticides.

scholarly journals Diffuse γ-ray emission toward the massive star-forming region, W40

2020 ◽  
Vol 639 ◽  
pp. A80
Author(s):  
Xiao-Na Sun ◽  
Rui-Zhi Yang ◽  
Yun-Feng Liang ◽  
Fang-Kun Peng ◽  
Hai-Ming Zhang ◽  
...  
Keyword(s):  
Cosmic Ray ◽  
High Energy ◽  
Young Star ◽  
Gas Content ◽  
Large Area ◽  
Stellar Cluster ◽  
Production Region ◽  
Star Forming ◽  
Photon Index ◽  
Young Star Clusters

We report the detection of high-energy γ-ray signal towards the young star-forming region, W40. Using 10-yr Pass 8 data from the Fermi Large Area Telescope (Fermi-LAT), we extracted an extended γ-ray excess region with a significance of ~18σ. The radiation has a spectrum with a photon index of 2.49 ± 0.01. The spatial correlation with the ionized gas content favors the hadronic origin of the γ-ray emission. The total cosmic-ray (CR) proton energy in the γ-ray production region is estimated to be the order of 1047 erg. However, this could be a small fraction of the total energy released in cosmic rays (CRs) by local accelerators, presumably by massive stars, over the lifetime of the system. If so, W40, together with earlier detections of γ-rays from Cygnus cocoon, Westerlund 1, Westerlund 2, NGC 3603, and 30 Dor C, supports the hypothesis that young star clusters are effective CR factories. The unique aspect of this result is that the γ-ray emission is detected, for the first time, from a stellar cluster itself, rather than from the surrounding “cocoons”.

scholarly journals Hyperfast pulsars as the remnants of massive stars ejected from young star clusters

2008 ◽  
Vol 385 (2) ◽  
pp. 929-938 ◽  
Author(s):  
Vasilii V. Gvaramadze ◽  
Alessia Gualandris ◽  
Simon Portegies Zwart
Keyword(s):  
Massive Stars ◽  
Star Clusters ◽  
Young Star ◽  
Young Star Clusters
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