Oxygen and nitrogen abundances of H <scp>ii</scp>regions in six spiral galaxies

Гусев, А. С.; Pilyugin, L. S.; Сахибов, Ф. Х.; Додонов, С. Н.; Ezhkova, O. V.; Khramtsova, M. S.

doi:10.1111/j.1365-2966.2012.21322.x

Cited by 28 publications

(35 citation statements)

References 62 publications

(117 reference statements)

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“…This equation fitted to the above data, including the central metallicity which we measure as 12 + log 10 (O/H) = 9.31 ± 0.18 using an SDSS spectrum taken at the center of the galaxy, gives 12 + log 10 (O/H) = 9.25 − 1.28 (r G /r 25 ) dex. This is a steeper gradient than the average for spirals (e.g., Pilyugin et al 2004;Gusev et al 2012). However, we note that in the above fit we are using the central oxygen abundance, without accounting for the possibility of AGN activity at the center of the galaxy.…”

Section: Metallicity Estimatesmentioning

confidence: 99%

“…13 Proposal ID 48-408, PI C. Fremling, conducted in service mode. Gusev et al (2012). The dashed blue line shows a firstorder polynomial fit which includes the central oxygen metallicity measured for NGC 5806 using an SDSS spectrum, and the dashed red line shows the same fit with the metallicity datapoint at the center of the galaxy excluded.…”

Section: Metallicity Estimatesmentioning

confidence: 99%

“…We show our measurements and gradients, along with the gradients of the sample of spiral galaxies studied by Gusev et al (2012), in Fig.2. The average gradient we find for NGC 5806 is in good agreement with this sample.…”

Section: Metallicity Estimatesmentioning

confidence: 99%

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PTF12os and iPTF13bvn

Fremling

Sollerman

Taddia

et al. 2016

A&A

180

169

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Context. We investigate two stripped-envelope supernovae (SNe) discovered in the nearby galaxy NGC 5806 by the (intermediate) Palomar Transient Factory [(i)PTF]. These SNe, designated PTF12os/SN 2012P and iPTF13bvn, exploded within ∼ 520 days of one another at a similar distance from the host-galaxy center. We classify PTF12os as a Type IIb SN based on our spectral sequence; iPTF13bvn has previously been classified as Type Ib having a likely progenitor with zero age main sequence (ZAMS) mass below ∼ 17 M . Because of the shared and nearby host, we are presented with a unique opportunity to compare these two SNe. Aims. Our main objective is to constrain the explosion parameters of iPTF12os and iPTF13bvn, and to put constraints on the SN progenitors. We also aim to spatially map the metallicity in the host galaxy, and to investigate the presence of hydrogen in early-time spectra of both SNe. Methods. We present comprehensive datasets collected on PTF12os and iPTF13bvn, and introduce a new automatic referencesubtraction photometry pipeline (FPipe) currently in use by the iPTF. We perform a detailed study of the light curves (LCs) and spectral evolution of the SNe. The bolometric LCs are modeled using the hydrodynamical code hyde. We analyze early spectra of both SNe to investigate the presence of hydrogen; for iPTF13bvn we also investigate the regions of the Paschen lines in infrared spectra. We perform spectral line analysis of helium and iron lines to map the ejecta structure of both SNe. We use nebular models and late-time spectroscopy to constrain the ZAMS mass of the progenitors. We also perform image registration of ground-based images of PTF12os to archival HST images of NGC 5806 to identify a potential progenitor candidate. Results. We find that our nebular spectroscopy of iPTF13bvn remains consistent with a low-mass progenitor, likely having a ZAMS mass of ∼ 12 M . Our late-time spectroscopy of PTF12os is consistent with a ZAMS mass of ∼ 15 M . We successfully identify a source in pre-explosion HST images coincident with PTF12os. The colors and absolute magnitude of this object are consistent between pre-explosion and late-time HST images, implying it is a cluster of massive stars. Our hydrodynamical modeling suggests that the progenitor of PTF12os had a compact He core with a mass of 3.25 −0.011 M of strongly mixed 56 Ni. Spectral comparisons to the Type IIb SN 2011dh indicate that the progenitor of PTF12os was surrounded by a thin hydrogen envelope with a mass lower than 0.02 M . We also find tentative evidence that the progenitor of iPTF13bvn could have been surrounded by a small amount of hydrogen prior to the explosion. This result is supported by possible weak signals of hydrogen in both optical and infrared spectra.

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Section: Metallicity Estimatesmentioning

confidence: 99%

Section: Metallicity Estimatesmentioning

confidence: 99%

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PTF12os and iPTF13bvn

Fremling

Sollerman

Taddia

et al. 2016

A&A

180

169

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“…Spectroscopy data (line intensities and EW (Hβ)) for IC 2574 are taken from Croxall et al (2009), data for NGC 628 are partly from Gusev et al (2012) and partly from van Zee et al (1998), data for NGC 6946 are taken from Gusev, Sakhibov & Dodonov (2013), and NGC 925 and NGC 3184 data are taken from van Zee et al (1998). Finally, NGC 3621 data are from Ryder (1995).…”

Section: Spectroscopic Datamentioning

confidence: 99%

Optical and infrared emission of H ii complexes as a clue to the PAH life cycle

Khramtsova¹,

Wiebe²,

Lozinskaya³

et al. 2014

Monthly Notices of the Royal Astronomical Society

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We present an analysis of optical spectroscopy and infrared aperture photometry of more than 100 H ii complexes in nine galaxies. Spectra obtained with the 6-m telescope of SAO RAS are used along with archival data from Spitzer and several ground-based telescopes to infer a strength of polycyclic aromatic hydrocarbon (PAH) emission, age, properties of the UV radiation field, and metallicity of studied H ii complexes. Physical properties (age, radiation field parameters, metallicity) are related to the F 8 /F 24 ratio used as a proxy for the PAH abundance in order to reveal factors that may influence the PAH evolution in H ii complexes. The well-known correlation between the F 8 /F 24 ratio and metallicity is confirmed in the studied complexes. The infrared flux ratio also correlates with the [O iii]λ5007/Hβ ratio which is often considered as an indicator of the radiation field hardness, but this correlation seems to be a mere reflection of a correlation between [O iii]λ5007/Hβ and metallicity. In separate metallicity bins, the F 8 /F 24 ratio is found to correlate with an age of an H ii complex, which is estimated from the equivalent width of Hβ line. The correlation is positive for low metallicity complexes and negative for high metallicity complexes. Analysing various mechanisms of PAH formation and destruction in the context of found correlations, we suggest that PAH abundance is likely altered by the UV radiation within H ii complexes, but this is not necessarily due to their destruction. If PAHs can also form in H ii complexes due to some processes like aromatisation, photodestruction, shattering and sputtering of very small grains, the net F 8 /F 24 ratio is determined by a balance between all these processes that can be different at different metallicities.

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“…Ivanov et al (1992) observed and compiled a catalogue of positions, angular sizes, integral magnitudes and H II identification of 147 OB associations and aggregates in NGC 628. Numerous star formation regions have been studied earlier based on photometric, spectroscopic and spectrophotometric observations (McCall, Rybski & Shields 1985;Belley & Roy 1992;Ferguson, Gallagher & Wyse 1998;Bresolin, Kennicutt & Garnett 1999;Larsen 1999Larsen , 2004Bruevich et al 2007;RosalesOrtega et al 2011;Gusev et al 2012;Berg et al 2013).…”

Section: Ngc 628 Previous Studiesmentioning

confidence: 99%

Star formation rates and the kinematics of gas in the spiral arms of NGC 628

2015

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Relations between star formation rates along the spiral arms and the velocities of gas inflow into the arms in grand-design galaxy NGC 628 were studied. We found that the radial distribution of average star formation rate in individual star formation regions in regular spiral arms correlates with the velocity of gas inflow into the spiral arms. Both distributions have maxima at a galactocentric distance of 4.5-5 kpc. There are no correlations between the radial distributions of average star formation rate in star formation regions in spiral arms and outside spiral arms in the main disc. We also did not find a correlation between the radial distribution of average star formation rate in star formation regions in spiral arms and H I column density.

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Oxygen and nitrogen abundances of H iiregions in six spiral galaxies

Cited by 28 publications

References 62 publications

PTF12os and iPTF13bvn

PTF12os and iPTF13bvn

Optical and infrared emission of H ii complexes as a clue to the PAH life cycle

Star formation rates and the kinematics of gas in the spiral arms of NGC 628

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