scholarly journals 3D optical spectroscopic study of NGC 3344 with SITELLE: I. Identification and confirmation of supernova remnants

2019 ◽  
Vol 488 (1) ◽  
pp. 803-829 ◽  
Author(s):  
I Moumen ◽  
C Robert ◽  
D Devost ◽  
R P Martin ◽  
L Rousseau-Nepton ◽  
...  
Keyword(s):  
Supernova Remnants ◽  
Flux Ratio ◽  
Large Magellanic Cloud ◽  
Emission Lines ◽  
Ionization Mechanism ◽  
H Ii Regions ◽  
Nearby Galaxy ◽  
Galactocentric Distance ◽  
Ionized Gas ◽  
Diffuse Ionized Gas

ABSTRACT We present the first optical identification and confirmation of a sample of supernova remnants (SNRs) in the nearby galaxy NGC 3344. Using high spectral and spatial resolution data, obtained with the CFHT imaging Fourier transform spectrograph SITELLE, we identified about 2200 emission line regions, many of which are H ii regions, diffuse ionized gas regions, and also SNRs. Considering the stellar population and diffuse ionized gas background, which are quite important in NGC 3344, we have selected 129 SNR candidates based on four criteria for regions where the emission lines flux ratio [S ii]/H α ≥ 0.4. Emission lines of [O ii] λ3727, H β, [O iii] λλ4959,5007, H α, [N ii] λλ6548,6583, and [S ii] λλ6716,6731 have been measured to study the ionized gas properties of the SNR candidates. We adopted a self-consistent spectroscopic analysis, based on Sabbadin plots and Baldwin, Phillips & Terlevich diagrams, to confirm the shock-heated nature of the ionization mechanism in the candidates sample. With this analysis, we end up with 42 Confirmed SNRs, 45 Probable SNRs, and 42 Less likely SNRs. Using shock models, the confirmed SNRs seem to have a metallicity ranging between Large Magellanic Cloud and 2×solar. We looked for correlations between the size of the confirmed SNRs and their emission lines ratios, their galaxy environment, and their galactocentric distance: We see a trend for a metallicity gradient among the SNR population, along with some evolutionary effects.

scholarly journals H ii regions in the CALIFA survey: I. catalogue presentation

2020 ◽  
Vol 494 (2) ◽  
pp. 1622-1646 ◽  
Author(s):  
C Espinosa-Ponce ◽  
S F Sánchez ◽  
C Morisset ◽  
J K Barrera-Ballesteros ◽  
L Galbany ◽  
...  
Keyword(s):  
Stellar Populations ◽  
Spectroscopic Properties ◽  
Emission Lines ◽  
H Ii Regions ◽  
Ionized Gas ◽  
New Approach ◽  
Integral Field Spectroscopy ◽  
Diffuse Ionized Gas ◽  
Spectroscopic Information ◽  
Selection Of

ABSTRACT We present a new catalogue of H ii regions based on the integral field spectroscopy (IFS) data of the extended CALIFA and PISCO samples. The selection of H ii regions was based on two assumptions: a clumpy structure with high contrast of H α emission and an underlying stellar population comprising young stars. The catalogue provides the spectroscopic information of 26 408 individual regions corresponding to 924 galaxies, including the flux intensities and equivalent widths of 51 emission lines covering the wavelength range between 3745 and 7200 Å. To our knowledge, this is the largest catalogue of spectroscopic properties of H ii regions. We explore a new approach to decontaminate the emission lines from diffuse ionized gas contribution. This diffuse gas correction was estimated to correct every emission line within the considered spectral range. With the catalogue of H ii regions corrected, new demarcation lines are proposed for the classical diagnostic diagrams. Finally, we study the properties of the underlying stellar populations of the H ii regions. It was found that there is a direct relationship between the ionization conditions on the nebulae and the properties of stellar populations besides the physicals condition on the ionized regions.

scholarly journals Diffuse ionized gas and its effects on nebular metallicity estimates of star-forming galaxies

2019 ◽  
Vol 489 (4) ◽  
pp. 4721-4733 ◽  
Author(s):  
N Vale Asari ◽  
G S Couto ◽  
R Cid Fernandes ◽  
G Stasińska ◽  
A L de Amorim ◽  
...  
Keyword(s):  
Formation Rate ◽  
Sloan Digital Sky Survey ◽  
Emission Lines ◽  
Strong Line ◽  
Galactocentric Distance ◽  
Ionized Gas ◽  
Star Forming ◽  
Diffuse Ionized Gas ◽  
Stellar Masses ◽  
The Impact

ABSTRACT We investigate the impact of the diffuse ionized gas (DIG) on abundance determinations in star-forming (SF) galaxies. The DIG is characterized using the H α equivalent width (WH α). From a set of 1 409 SF galaxies from the Mapping Nearby Galaxies at APO (MaNGA) survey, we calculate the fractional contribution of the DIG to several emission lines using high-S/N data from SF spaxels (instead of using noisy emission-lines in DIG-dominated spaxels). Our method is applicable to spectra with observed WH α ≳ 10 Å (which are not dominated by DIG emission). Since the DIG contribution depends on galactocentric distance, we provide DIG-correction formulae for both entire galaxies and single aperture spectra. Applying those to a sample of $\, \gt 90\, 000$ SF galaxies from the Sloan Digital Sky Survey, we find the following. (1) The effect of the DIG on strong-line abundances depends on the index used. It is negligible for the ([O iii]/H β)/([N ii]/H α) index, but reaches ∼0.1 dex at the high-metallicity end for [N ii]/H α. (2) This result is based on the ∼kpc MaNGA resolution, so the real effect of the DIG is likely greater. (3) We revisit the mass–metallicity–star formation rate (SFR) relation by correcting for the DIG contribution in both abundances and SFR. The effect of DIG removal is more prominent at higher stellar masses. Using the [N ii]/Hα index, O/H increases with SFR at high stellar mass, contrary to previous claims.

scholarly journals Imaging and spectroscopy of the LMC He II nebula N 44C and its ionizing star

1999 ◽  
Vol 193 ◽  
pp. 480-481
Author(s):  
Vanessa C. Galarza ◽  
Donald R. Garnett ◽  
You-Hua Chu
Keyword(s):  
Large Magellanic Cloud ◽  
Convincing Evidence ◽  
H Ii Regions ◽  
Uv Spectrum ◽  
Ionized Gas ◽  
X Ray ◽  
H Ii Region ◽  
Recombination Emission ◽  
Imaging And Spectroscopy ◽  
Echelle Spectroscopy

We present results from new HST imaging and spectroscopy of the peculiar Large Magellanic Cloud H II region N 44C and its ionizing star. While this nebula exhibits strong He II recombination emission, the source of the He+ ionizing photons has not been found. The UV spectrum of the ionizing star suggests an approximate spectral class of 07–08; the UV Si IV, He II, and N IV features do not show P-Cygni profiles, indicating that the ionizing star is not a supergiant. No companion star has yet been detected. Ground-based and HST optical spectroscopy of the ionized gas shows that the nebular abundances of C, N, O and He are not anomalous relative to other LMC H II regions, suggesting that no previous WR/SN companion has disappeared. Echelle spectroscopy has also ruled out the presence of high velocity shocked gas. Deep ROSAT imaging shows no X-ray point source in this location. The “fossil X-ray binary” hypothesis of Pakull & Motch (1989) remains the best explanation for the ionization of this nebula; however, convincing evidence for this hypothesis remains elusive.

scholarly journals The effects of diffuse ionized gas and spatial resolution on metallicity gradients: TYPHOON two-dimensional spectrophotometry of M83

2019 ◽  
Vol 487 (1) ◽  
pp. 79-96 ◽  
Author(s):  
Henry Poetrodjojo ◽  
Joshua J D’Agostino ◽  
Brent Groves ◽  
Lisa Kewley ◽  
I-Ting Ho ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Systematic Study ◽  
Surface Brightness ◽  
H Ii Regions ◽  
Two Dimensional ◽  
Ionized Gas ◽  
Data Cubes ◽  
Radial Profiles ◽  
Diffuse Ionized Gas ◽  
Spectrophotometric Data

Abstract We present a systematic study of the diffuse ionized gas (DIG) in M83 and its effects on the measurement of metallicity gradients at varying resolution scales. Using spectrophotometric data cubes of M83 obtained at the 2.5m duPont telescope at Las Campanas Observatory as part of the TYPHOON programme, we separate the H ii regions from the DIG using the [S ii]/H α ratio, HIIphot (H ii-finding algorithm), and the H α surface brightness. We find that the contribution to the overall H α luminosity is approximately equal for the H ii and DIG regions. The data is then rebinned to simulate low-resolution observations at varying resolution scales from 41 pc up to 1005 pc. Metallicity gradients are measured using five different metallicity diagnostics at each resolution. We find that all metallicity diagnostics used are affected by the inclusion of DIG to varying degrees. We discuss the reasons why the metallicity gradients are significantly affected by DIG using the H ii dominance and emission line ratio radial profiles. We find that applying the [S ii]/H α cut will provide a closer estimate of the true metallicity gradient up to a resolution of 1005 pc for all metallicity diagnostics used in this study.

scholarly journals Infrared Coronal Emission Lines and the Possibility of their Laser Emission in Seyfert Nuclei

1994 ◽  
Vol 159 ◽  
pp. 447-447
Author(s):  
Matthew A. Greenhouse ◽  
Uri Feldman ◽  
Howard A. Smith ◽  
Marcel Klapisch ◽  
Anand K. Bhatia ◽  
...  
Keyword(s):  
Supernova Remnants ◽  
Detailed Balance ◽  
Galaxy Cluster ◽  
Emission Lines ◽  
Density Parameter ◽  
Coronal Emission ◽  
Ionized Gas ◽  
Cooling Flows ◽  
Relationship Of ◽  
The Relationship

Infrared coronal emission lines are providing a new window for observation and analysis of highly ionized gas in Galactic and extragalactic sources such as Seyfert nuclei and classical novae shells. These lines are expected to be primary coolants in colliding galaxies, galaxy cluster cooling flows, cometary-compact HII regions, and supernova remnants. In this poster, we summarize results discussed in detail by Greenhouse et al. 1993, ApJS, 88, 23. We discuss approximately 74 infrared (1 < λ μm < 280) transitions within the ground configurations 2s22pk and 3s23pk (k = 1 to 5) or the first excited configurations 2s2p and 3s3p of highly ionized (χ ≥ 100 eV) O, Ne, Na, Mg, Al, Si, S, Ar, Ca, Fe, and Ni. We present results from detailed balance calculations, critical densities for collisional de-excitation, intrinsic photon rates, branching ratios, and excitation temperatures for the transitions. The temperature and density parameter space for dominant cooling via infrared coronal lines is presented, and the relationship of infrared and optical coronal lines is discussed.

Diffuse Ionized Gas in Spiral Galaxies: Probing Lyman Continuum Photon Leakage From H II Regions?

1996 ◽  
Vol 111 ◽  
pp. 2265 ◽  
Author(s):  
Annette M. N. Ferguson ◽  
Rosemary F. G. Wyse ◽  
J. S., III Gallagher ◽  
Deidre A. Hunter
Keyword(s):  
Spiral Galaxies ◽  
H Ii Regions ◽  
Ionized Gas ◽  
Lyman Continuum ◽  
Diffuse Ionized Gas

scholarly journals Understanding Galaxy Evolution Through Emission Lines

2019 ◽  
Vol 57 (1) ◽  
pp. 511-570 ◽  
Author(s):  
Lisa J. Kewley ◽  
David C. Nicholls ◽  
Ralph S. Sutherland
Keyword(s):  
Emission Line ◽  
Galaxy Evolution ◽  
Sample Selection ◽  
Cosmic Time ◽  
Emission Lines ◽  
Ionized Gas ◽  
Fundamental Properties ◽  
Integral Field Spectroscopy ◽  
Diffuse Ionized Gas ◽  
Ionization Parameter

We review the use of emission lines for understanding galaxy evolution, focusing on excitation source, metallicity, ionization parameter, ISM pressure, and electron density. We discuss the physics, benefits, and caveats of emission line diagnostics, including the effects of theoretical model uncertainties, diffuse ionized gas, and sample selection bias. In anticipation of upcoming telescope facilities, we provide new self-consistent emission line diagnostic calibrations for complete spectral coverage from the UV to the IR. These diagnostics can be used in concert to understand how fundamental galaxy properties have changed across cosmic time. We conclude the following: ▪ The UV, optical, and IR contain complementary diagnostics that can probe the conditions within different nebular ionization zones. ▪ Accounting for complex density gradients and temperature profiles is critical for reliably estimating the fundamental properties of Hii regions and galaxies. ▪ Diffuse ionized gas can raise metallicity estimates, flatten metallicity gradients, and introduce scatter in ionization parameter measurements. ▪ New 3D emission line diagnostics successfully separate the contributions from star formation, AGN, and shocks using integral field spectroscopy. We summarize with a discussion of the challenges and major opportunities for emission line diagnostics in the coming years.

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