scholarly journals The Origins of Planetary Nebulae in the Inner and Outer Disks of M 31

2016 ◽  
Vol 12 (S323) ◽  
pp. 264-268
Author(s):  
Bruce Balick ◽  
Karen Kwitter ◽  
Romano Corradi ◽  
Rebeca Galera Rosillo ◽  
Richard Henry
Keyword(s):  
Chemical Evolution ◽  
Stellar Population ◽  
Milky Way ◽  
Planetary Nebulae ◽  
Radial Gradient ◽  
M 31 ◽  
Stark Contrast ◽  
Entire Ensemble

AbstractThe planetary nebulae (PNe) of M 31 are receiving considerable attention as probes of its structure and chemical evolution in a galactic environment that is putatively similar to the Milky Way. We have obtained deep spectra for about 30 luminous PNe in M 31’s inner disk and beyond (Rgal < 105 kpc). The entire ensemble of PNe exhibit O/H ~ 2/3 solar with no discernible radial gradient, in stark contrast to the H ii regions of M 31. This suggests that the outer PNe in M 31 formed from a common O-rich ISM at least 5 GY ago. We infer that the outer PNe and the underlying stellar population have little common history in M 31, and that the formation of the O-rich PNe preceded any putative encounter with M 33 ~2–3 Gy ago.

scholarly journals The survey of planetary nebulae in Andromeda (M 31)

2019 ◽  
Vol 624 ◽  
pp. A132 ◽  
Author(s):  
Souradeep Bhattacharya ◽  
Magda Arnaboldi ◽  
Johanna Hartke ◽  
Ortwin Gerhard ◽  
Valentin Comte ◽  
...  
Keyword(s):  
Luminosity Function ◽  
Stellar Population ◽  
Milky Way ◽  
Planetary Nebulae ◽  
Significant Rise ◽  
Minor Axis ◽  
Wide Field ◽  
Detection Techniques ◽  
Current Survey ◽  
M 31

Context.The Andromeda (M 31) galaxy subtends nearly 100 square degrees on the sky. Any study of its halo must therefore account for the severe contamination from the Milky Way halo stars whose surface density displays a steep gradient across the entire M 31 field of view.Aims.Our goal is to identify a population of stars firmly associated with the M 31 galaxy. Planetary nebulae (PNe) are one such population that are excellent tracers of light, chemistry, and motion in galaxies. We present a 16 square degree survey of the disc and inner halo of M 31 with the MegaCam wide-field imager at the CFHT to identify PNe, and characterise the luminosity-specific PN number and PN luminosity function (PNLF) in M 31.Methods.PNe were identified via automated detection techniques based on their bright [O III] 5007 Å emission and absence of a continuum. Subsamples of the faint PNe were independently confirmed by matching with resolvedHubbleSpace Telescope sources from the PanchromaticHubbleAndromeda Treasury and spectroscopic follow-up observations with HectoSpec at the MMT.Results.The current survey reaches two magnitudes fainter than the previous most sensitive survey. We thus identify 4289 PNe, of which only 1099 were previously known. By comparing the PN number density with the surface brightness profile of M 31 out to ∼30 kpc along the minor axis, we find that the stellar population in the inner halo has a luminosity-specific PN number value that is seven times higher than that of the disc. We measure the luminosity function of the PN population and find a bright cut-off and a slope consistent with previous determinations. Interestingly, it shows a significant rise at the faint end, present in all radial bins covered by the survey. This rise in the M 31 PNLF is much steeper than that observed for the Magellanic clouds and Milky Way bulge.Conclusions.The significant radial variation of the PN specific frequency value indicates that the stellar population at deprojected minor-axis radii larger than ∼10 kpc is different from that in the disc of M 31. The rise at the faint end of the PNLF is a property of the late phases of the stellar population. M 31 shows two major episodes of star formation and the rise at the faint end of the PNLF is possibly associated with the older stellar population. It may also be a result of varying opacity of the PNe.

scholarly journals Carbon, nitrogen and oxygen abundance gradients in M101 and M31

2019 ◽  
Author(s):  
C Esteban ◽  
F Bresolin ◽  
J García-Rojas ◽  
L Toribio San Cipriano
Keyword(s):  
Milky Way ◽  
Spiral Galaxies ◽  
Effective Radius ◽  
H Ii Regions ◽  
Apparent Contradiction ◽  
Radial Gradient ◽  
A Value ◽  
C And N ◽  
M 31 ◽  
Significant Chemical

Abstract We present deep spectrophotometry of 18 H ii regions in the nearby massive spiral galaxies M 101 and M 31. We have obtained direct determinations of electron temperature in all the nebulae. We detect the C ii 4267 Å line in several H ii regions, permitting to derive the radial gradient of C/H in both galaxies. We also determine the radial gradients of O/H, N/O, Ne/O, S/O, Cl/O and Ar/O ratios. As in other spiral galaxies, the C/H gradients are steeper than those of O/H producing negative slopes of the C/O gradient. The scatter of the abundances of O with respect to the gradient fittings do not support the presence of significant chemical inhomogeneities across the discs of the galaxies, especially in the case of M101. We find trends in the S/O, Cl/O and Ar/O ratios as a function of O/H in M101 that can be reduced using Te indicators different from the standard ones for calculating some ionic abundances. The distribution of the N/O ratio with respect to O/H is rather flat in M31, similarly to previous findings for the Milky Way. Using the disc effective radius – Re – as a normalization parameter for comparing gradients, we find that the latest estimates of Re for the Milky Way provide an excess of metallicity in apparent contradiction with the mass-metallicity relation; a value about two times larger might solve the problem. Finally, using different abundance ratios diagrams we find that the enrichment timescales of C and N result to be fairly similar despite their different nucleosynthetic origin.

scholarly journals Some aspects of the chemical evolution of 4He in the Galaxy: the He/H radial gradient and the ΔY/ΔZ enrichment ratio

2000 ◽  
Vol 198 ◽  
pp. 204-213
Author(s):  
W. J. Maciel
Keyword(s):  
Chemical Evolution ◽  
Heavy Element ◽  
Planetary Nebulae ◽  
Enrichment Ratio ◽  
Radial Gradient ◽  
The Galaxy ◽  
Element Enrichment ◽  
Progenitor Stars

Two aspects of the chemical evolution of 4He in the Galaxy are considered on the basis of a sample of disk planetary nebulae by the application of corrections due to the contamination of 4He from the progenitor stars. First, the He/H radial gradient is analyzed, and then, the helium to heavy element enrichment ratio is determined for metallicities up to the solar value.

scholarly journals AGB stars and galactic dynamics

1999 ◽  
Vol 191 ◽  
pp. 500-510 ◽  
Author(s):  
H. Dejonghe ◽  
K. Van Caelenberg
Keyword(s):  
Chemical Composition ◽  
Stellar Population ◽  
Milky Way ◽  
Planetary Nebulae ◽  
Line Of Sight ◽  
Galactic Dynamics ◽  
Stellar Systems ◽  
Agb Stars ◽  
Dynamical Models ◽  
Ir Stars

AGB stars, seen as a stellar population, can be used to probe the dynamical state of galaxies. The relevant data are mostly positions and line-of-sight velocities, sometimes together with information on chemical composition and/or age. As of now, dynamical models have been made for OH/IR stars and Planetary Nebulae. Other candidates are C stars, S stars, and Miras. We review the methods used and the results obtained so far, for the Milky Way and for (relatively nearby) extragalactic stellar systems.

Metallicity gradients in M31, M33, NGC 300, and Milky Way using Argon abundances

2018 ◽  
Vol 14 (A30) ◽  
pp. 268-268
Author(s):  
Sheila N. Flores-Durán ◽  
Miriam Peña
Keyword(s):  
Milky Way ◽  
Planetary Nebulae ◽  
H Ii Regions ◽  
Chemical Abundances ◽  
Local Universe ◽  
Homogeneous Sample ◽  
M 31

AbstractWe studied Planetary Nebulae (PNe) metallicity gradients using Ar abundances. We compared them with H ii regions in the galaxies of the local universe M 31, M 33, NGC 300 and in the Milky Way. Galactocentric radio (RG) and chemical abundances were collected from the literature, carefully selecting an homogeneous sample for each galaxy. In these galaxies, metallicity gradients computed with PNe abundances are flatter than those of H ii regions.

scholarly journals Chemical evolution models for spiral disks: the Milky Way, M 31, and M 33

2010 ◽  
Vol 520 ◽  
pp. A35 ◽  
Author(s):  
M. M. Marcon-Uchida ◽  
F. Matteucci ◽  
R. D. D. Costa
Keyword(s):  
Chemical Evolution ◽  
Milky Way ◽  
M 31

Further exploration of Galactic disk abundance gradients

2011 ◽  
Vol 7 (S283) ◽  
pp. 438-439
Author(s):  
Jackie B. Milingo ◽  
Richard B. C. Henry ◽  
Karen B. Kwitter ◽  
Bruce Balick
Keyword(s):  
Regression Analysis ◽  
Milky Way ◽  
Galactic Disk ◽  
Planetary Nebulae ◽  
Galactocentric Distance ◽  
Abundance Gradient ◽  
Radial Gradient

AbstractWe examine the abundance gradient in the Milky Way disk via homogeneously determined data for 124 Galactic planetary nebulae (PNe). We present recent results from a detailed regression analysis of the O gradient. With O, Ne, S, Cl, and Ar available and a range of galactocentric distance (Rg) from 0.9 to 21 kpc, we present additional exploration of the disk radial gradient by statistically analyzing a series of short segments of increasing average Rg.

scholarly journals Abundance gradients: tracing the chemical properties of the disk

2009 ◽  
Vol 5 (H15) ◽  
pp. 790-790
Author(s):  
Roberto D.D. Costa ◽  
Walter J. Maciel
Keyword(s):  
Time Evolution ◽  
Chemical Evolution ◽  
Galactic Disk ◽  
Chemical Properties ◽  
Planetary Nebulae ◽  
Hii Regions ◽  
B Stars ◽  
Radial Gradient ◽  
The Galaxy ◽  
Vertical Gradients

AbstractAbundance gradients are key parameters to constrain the chemical evolution of the galactic disk. In this review recent determinations for the radial gradient are described, including its slope as derived from different objects such as planetary nebulae, HII regions, cepheids, or B stars, and for different elements. Inner and outer limits for the radial gradient, as well as its time evolution, both related to the chemical evolution of the Galaxy, are also described. The possible existence of azimuthal and vertical gradients is also discussed.

scholarly journals METALLICITY GRADIENTS IN M31, M 33, NGC 300 AND THE MILKY WAY USING ABUNDANCES OF DIFFERENT ELEMENTS

2019 ◽  
Vol 55 (2) ◽  
pp. 255-271 ◽  
Author(s):  
Miriam Peña ◽  
Sheila N. Flores-Durán
Keyword(s):  
Milky Way ◽  
Planetary Nebulae ◽  
Extreme Case ◽  
H Ii Regions ◽  
Type I ◽  
Chemical Abundances ◽  
Homogeneous Sample ◽  
Radial Migration ◽  
Chemical Gradients ◽  
M 31

Metallicity gradients derived from planetary nebulae (PNe) using O, Ne, and Ar abundances are studied and compared to those from H ii regions in the galaxies M 31, M 33, NGC 300 and the Milky Way. Galactocentric radii and chemical abundances were collected from the literature, carefully selecting a homogeneous sample for each galaxy. Metallicity gradients shown by PNe are flatter than those of H ii regions in all cases. The extreme case is M 31 where PN abundances are not related to galactocentric distances and the gradients are consistent with zero. To analyze the evolution of gradients with time we build gradients for Peimbert Type I and non-Type I PNe finding that Type I PNe show steeper gradients than non-Type I PNe and more similar to the ones of H ii regions indicating that the chemical gradients might steepen with time. Alternatively, the flat gradients for old PNe show that radial migration could have an important role in the evolution of galaxies.

scholarly journals The population of Planetary Nebulae in the Milky Way

2009 ◽  
Vol 5 (H15) ◽  
pp. 806-806
Author(s):  
Romano L. M. Corradi
Keyword(s):  
Chemical Evolution ◽  
White Dwarf ◽  
Milky Way ◽  
Planetary Nebulae ◽  
Morphological Properties ◽  
Global View ◽  
The Galaxy ◽  
Red Giant

AbstractExtensive surveys of the Milky Way have provided a global view of the population of planetary nebulae in the Milky Way. Their chemical, dynamical, and morphological properties, the link with their red giant progenitors and white dwarf descendants, and the implications on our understanding of the chemical evolution of the Galaxy, are discussed.

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