On the Reaction of 3-Phenylcoumarin with Organomagnesium Compounds

Ivanov, C.; Bojilova, A.

doi:10.1055/s-1974-23408

Cited by 24 publications

(12 citation statements)

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“…This is an interesting result, considering that this size is comparable (but still to the upper limit) to the typical size for giant molecular clouds (e.g., Cox 2000;Tielens 2005). It has been also pointed out earlier by various authors (e.g., Efremov et al 1987;Ivanov 1996) that young stellar associations in different galaxies have dimensions that average at ∼ 80 pc, comparable to the 40% percentile of our distribution. Considering that the determination of structures dimensions is sensitive to the resolution of their detection, the question if this length-scale would represent a characteristic scale for star formation is still open (e.g., Bastian et al 2007;Gouliermis 2011).…”

Section: Parameters Demographicssupporting

confidence: 87%

Hierarchical star formation across the ring galaxy NGC 6503

Gouliermis¹,

Thilker²,

Elmegreen³

et al. 2015

Mon. Not. R. Astron. Soc.

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We present a detailed clustering analysis of the young stellar population across the starforming ring galaxy NGC 6503, based on the deep HST photometry obtained with the Legacy ExtraGalactic UV Survey (LEGUS). We apply a contour-based map analysis technique and identify in the stellar surface density map 244 distinct star-forming structures at various levels of significance. These stellar complexes are found to be organized in a hierarchical fashion with 95% being members of three dominant super-structures located along the star-forming ring. The size distribution of the identified structures and the correlation between their radii and numbers of stellar members show power-law behaviors, as expected from scale-free processes. The self-similar distribution of young stars is further quantified from their autocorrelation function, with a fractal dimension of ∼ 1.7 for length-scales between ∼ 20 pc and 2.5 kpc. The young stellar radial distribution sets the extent of the star-forming ring at radial distances between 1 and 2.5 kpc. About 60% of the young stars belong to the detected stellar structures, while the remaining stars are distributed among the complexes, still inside the ring of the galaxy. The analysis of the time-dependent clustering of young populations shows a significant change from a more clustered to a more distributed behavior in a time-scale of ∼ 60 Myr. The observed hierarchy in stellar clustering is consistent with star formation being regulated by turbulence across the ring. The rotational velocity difference between the edges of the ring suggests shear as the driving mechanism for this process. Our findings reveal the interesting case of an inner ring forming stars in a hierarchical fashion.

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Section: Parameters Demographicssupporting

confidence: 87%

Hierarchical star formation across the ring galaxy NGC 6503

Gouliermis¹,

Thilker²,

Elmegreen³

et al. 2015

Mon. Not. R. Astron. Soc.

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“…As these clumps are bright in FUV, it is possible that some of them are OB associations. The sizes of OB associations cover a range between 10 -100 pc for the Milky way and other nearby spiral and dwarf galaxies (Mel'Nik & Efremov 1995;Bresolin et al 1996;Ivanov 1996;Bresolin et al 1998;Bastian et al 2007). Therefore, the galaxy IC 2574 have produced OB associations which are similar in size with those of other nearby galaxies.…”

Section: Discussionmentioning

confidence: 99%

Ultraviolet Imaging Telescope View of Dwarf Irregular Galaxy IC 2574: Is the Star Formation Triggered Due to Expanding H i Shells?

Mondal

Subramaniam

George

2019

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Star forming dwarf galaxies in the local volume are diverse and are ideal test beds to understand details of star formation in a variety of environments. Here, we present a deep FUV imaging study of a nearby dwarf irregular galaxy IC 2574 using the Ultraviolet Imaging Telescope (UVIT). We identified 419 FUV bright regions with radii between 15 -285 pc in the galaxy and found that 28.6% of them to be located in H I shells, 12.6% inside holes and 60.1% to be away from the holes. The H I column density is found to be more than 10 21 cm −2 for 82.3% of the identified regions. 30 out of the 48 H I holes show triggered star formation in their shells while 16 holes do not show any related FUV emission. Cross-matching with Hα emission, we found that 23 holes have both FUV and Hα emission in their shells signifying very recent trigger. Therefore, star formation in the galaxy has been partly triggered due to the expanding H I holes whereas in majority of the sites it is driven by other mechanisms. Irrespective of the location, larger star forming complexes were found to have multiple sub-structures. We report two resolved components for the remnant cluster of the super giant shell and estimated their masses. The star formation rate of IC 2574 is found to be 0.57 M /yr, which is slightly higher compared to the average value of other nearby dwarf irregular galaxies.

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“…Bresolin et al (1998) studied OB associations in 7 nearby spiral galaxies using HST-WFPC2 data and found a size range of ∼ 70 -100 pc. For nearby irregular galaxies, the size of OB associations are reported to be ∼ 80 pc by Ivanov (1996). Mel'Nik & Efremov (1995) found relatively smaller size (∼ 10 -80 pc, with a peak around 30 pc) for galactic OB association whereas for LMC and SMC, it is around 60 pc (Bresolin et al 1996).…”

Section: Star Formation Ratementioning

confidence: 99%

UVIT Imaging of WLM: Demographics of Star-forming Regions in the Nearby Dwarf Irregular Galaxy

Mondal

Subramaniam

George

2018

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We present a study of star forming regions and its demographics in the nearby dwarf irregular galaxy WLM using the Ultra-Violet Imaging Telescope (UVIT) multi band observations in three filters F148W, N245M and N263M. We find that the UV emission is extended at least up to 1.7 kpc, with the NUV emission more extended than the FUV. We create UV color maps ((F148W−N245M) and (F148W−N263M)) to study the temperature morphology of young stellar complexes with the help of theoretical models. We identify several complexes with temperature T > 17500 K which are likely to be the OB associations present in the galaxy. These complexes show good spatial correlation with the Hα emitting regions, H I distribution and HST detected hot stars. The hot star forming regions are found to be clumpy in nature and show a hierarchical structure, with sizes in the range of 4 -50 pc, with a large number with sizes < 10 pc. The south western part of the galaxy shows many hot star forming regions, high level of Hα emission and low column density of H I which altogether denote a vigorous recent star formation. WLM is likely to have a large fraction of low mass compact star forming regions with mass M < 10 3 M , in agreement with the size and mass of the CO clouds. We estimate the star formation rate of WLM to be ∼ 0.008 M /yr, which is similar to the average value measured for nearby dwarf irregular galaxies.

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On the Reaction of 3-Phenylcoumarin with Organomagnesium Compounds

Cited by 24 publications

References 0 publications

Hierarchical star formation across the ring galaxy NGC 6503

Hierarchical star formation across the ring galaxy NGC 6503

Ultraviolet Imaging Telescope View of Dwarf Irregular Galaxy IC 2574: Is the Star Formation Triggered Due to Expanding H i Shells?

UVIT Imaging of WLM: Demographics of Star-forming Regions in the Nearby Dwarf Irregular Galaxy

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