- ID:
- ivo://CDS.VizieR/J/ApJ/414/463
- Title:
- Planetary nebula system of NGC 5128
- Short Name:
- J/ApJ/414/463
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the result of a planetary nebula (PN) survey of the nearby giant elliptical galaxy NGC 5128 performed with CCD cameras at the prime focus of the CTIO 4m in telescope. By comparing CCD images centered on the characteristic emission line [O III] {lambda}5007{AA} and on the adjacent continuum, we identify a total of 785 PNs in areas extending 20kpc along the photometric major axis and covering the whole galaxy to 10kpc. From these data, we form a complete sample of 224 PN's extending to a dereddened limiting magnitude of m_5007_=24.8, which extends 1.5mag down the PN luminosity function (PNLF). Adopting a foreground extinction of E(B-V)=0.1, we derive a distance to the galaxy of 3.5+/-0.2Mpc, in excellent agreement with the surface brightness fluctuation method. No population effect on the bright cutoff of PNLF is observed in the isophotal radius range of 2-16kpc, but the luminosity specific PN density ({alpha}_2.5_) seems to increase with radius inside of 7kpc, in agreement with the {alpha}_2.5_-color relation observed for other galaxies.
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Search Results
202. PN abundances
- ID:
- ivo://CDS.VizieR/J/A+AS/126/297
- Title:
- PN abundances
- Short Name:
- J/A+AS/126/297
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Abundance determinations of about 110 planetary nebulae, which are likely to be in the Galactic Bulge are presented. Plasma diagnostics have been performed by making use of the available forbidden line ratios combined with radio continuum measurements. Chemical abundances of He, O, N, Ne, S, Ar, and Cl are then derived by employing theoretical nebular models as interpolation devices in establishing the ionization correction factors (ICFs) used to estimate the distribution of atoms among unobserved ionization stages. The overall agreement between the results derived by using the model-ICFs and those obtained from the theoretical models is reasonably good. The uncertainties related to the total abundances show a clear dependence on the level of excitation. In most cases, the abundances of chlorine can be derived only in objects with a relatively high Cl-abundance. Contrary to the conclusion previously drawn by Webster (1988MNRAS.230..377W), we found the excitation classes are not uniformly distributed. A clear peak at about classes 5 and 6 is noticed. The distribution is shifted toward a lower excitation range with respect to that of the nearby nebulae, reflecting the difference in the central star temperature distribution between the two samples.
- ID:
- ivo://CDS.VizieR/J/A+A/336/667
- Title:
- PN abundances in five galaxies
- Short Name:
- J/A+A/336/667
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have collected photometric and spectroscopic data on planetary nebulae (PNe) in 5 galaxies: the Milky Way (bulge), M31 (bulge), M 32, the LMC and the SMC. We have computed the abundances of O, Ne and N and compared them from one galaxy to another. In each Galaxy, the distribution of oxygen abundances has a large dispersion. The average O/H ratio is larger in the M31 and the Galactic bulge PNe than in those in the Magellanic Clouds. In a given galaxy, it is also larger for PNe with [OIII] luminosities greater than 100L_{sun}_, which are likely to probe more recent epochs in the galaxy history. We find that the M31 and the Galactic bulge PNe extend the very tight Ne/H-O/H correlation observed in the Galactic disk and Magellanic Clouds PNe towards higher metallicities. We note that the anticorrelation between N/O and O/H that was known to occur in the Magellanic Clouds and in the disk PNe is also marginally found in the PNe of the Galactic bulge. Furthermore, we find that high N/O ratios are higher for less luminous PNe. In M 32, all PNe have a large N/O ratio, indicating that the stellar nitrogen abundance is enhanced in this galaxy. We have also compared the PN evolution in the different galactic systems by constructing diagrams that are independent of abundances, and have found strikingly different behaviours of the various samples. In order to help in the interpretation of these data, we have constructed a grid of expanding, PN photoionization models in which the central stars evolve according to the evolutionary tracks of Bloecker (1995A&A...299..755B). These models show that the apparent spectroscopic properties of PNe are extremely dependent, not only on the central stars, but also on the masses and expansion velocities of the nebular envelopes. The main conclusion of the confrontation of the observed samples with the model grids is that the PN populations are indeed not the same in the various parent galaxies. Both stars and nebulae are different. In particular, the central stars of the Magellanic Clouds PNe are shown to evolve differently from the hydrogen burning stellar evolutionary models of Bloecker (1995). In the Galactic bulge, on the other hand, the behaviour of the observed PNe is roughly compatible with the theoretical stellar evolutionary tracks. The case of M31 is not quite clear, and additional observations are necessary. It seems that the central star mass distribution is narrower for the M31 PNe than for the Galactic bulge PNe. We show that spectroscopy of complete samples of PNe down to a factor 100 below the maximum luminosity would help to better characterize the PN central star mass distribution.
- ID:
- ivo://CDS.VizieR/J/A+A/495/447
- Title:
- PN and HII regions in NGC6822
- Short Name:
- J/A+A/495/447
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Images obtained with the CTIO 4-m telescope and the MOSAIC-2 wide field camera in [OIII] 5007 and Halpha on-band and off-band filters are analyzed to search for emission line objects in the dwarf galaxy NGC 6822. In particular we search for planetary nebula (PN) candidates. In addition, imaging and spectroscopy of a sub-sample of objects obtained with the ESO VLT and FORS 2 spectrograph are used to calibrate the MOSAIC imaging. In the continuum-subtracted images, a large number of line emission regions were detected, for which we measured instrumental magnitudes in all the filters. The [OIII] 5007 and Halpha+[NII] magnitudes were calibrated with the spectroscopy.
- ID:
- ivo://CDS.VizieR/J/A+A/466/75
- Title:
- PN and HII regions of West and East of NGC 3109
- Short Name:
- J/A+A/466/75
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Images obtained with the ESO VLT and FORS1 in [O III] 5007 on- and off-band, as well as r_Gunn filters, are analyzed to search for planetary nebula (PN) candidates. In the continuum-subtracted [O III] 5007 on-band images, a large number of emission-line regions were detected. We describe the criteria employed for distinguishing PN candidates from compact HII regions.
206. PN distance scale
- ID:
- ivo://CDS.VizieR/J/A+AS/108/485
- Title:
- PN distance scale
- Short Name:
- J/A+AS/108/485
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/A+A/306/9
- Title:
- PNe and HII in NGC 300
- Short Name:
- J/A+A/306/9
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report a search for planetary nebulae and H II regions in the central part of the late-type spiral NGC 300, using a CCD and the on-band/off-band filter technique. The total exposure time for all frames was 4 hours. We have identified 34 PNs and 88 H II regions. We construct the cumulative [O III] {lambda}5007 PN luminosity function (PNLF) and obtain a distance modulus of 26.9+/-0.4, in satisfactory agreement with the Cepheid distance modulus (26.7+/-0.1). We make a general comparison between Cepheid and PNLF distances, showing that they are in excellent overall agreement. NGC 300 is in principle one of the best possible calibrators of the PNLF method of distance determination, to be preferentially applied, like the LMC, in cases of populations with recent star formation (as opposed to the bulge of M 31, which has served as calibrator for populations without recent star formation).
- ID:
- ivo://CDS.VizieR/J/MNRAS/428/3443
- Title:
- PNe and HII regions plasma diagnostics
- Short Name:
- J/MNRAS/428/3443
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We carry out plasma diagnostic analyses for 123 planetary nebulae (PNe) and 42 HII regions using the NII and OII optical recombination lines (ORLs). New effective recombination coefficients for the NII and OII optical recombination spectra are used. These data were calculated under the intermediate coupling scheme for a number of electron temperature (Te) and density (Ne) cases. We use a new method to determine the Te's and Ne's for the nebular sample, combining the ORLs with the most reliable measurements for each ion and the predicted intensities that are based on the new atomic data. Uncertainties of the derived Te and Ne are estimated for each object. The diagnostic results from heavy element ORLs show reasonable agreement with previous calculations in the literature. We compare the electron temperatures derived from the NII and OII ORLs, Te(ORLs), and those from the collisionally excited lines (CELs), Te(CELs), as well as the hydrogen Balmer jump, Te(HIBJ), especially for the PNe with large abundance discrepancies. Temperatures from the HeI recombination lines, Te(HeI), are also used for comparison if available. For all the objects included in our sample, Te(ORLs) are lower than Te(HIBJ), which are in turn systematically lower than Te(CELs). PNe with Te(HeI) available show the relation Te(ORLs)<=Te(HeI)<=Te(HIBJ)<=Te(CELs), which is consistent with predictions from the bi-abundance nebular model postulated by Liu et al. (2000MNRAS.312..585L).
- ID:
- ivo://CDS.VizieR/J/ApJ/635/290
- Title:
- PNe and stellar kinematics in NGC1344
- Short Name:
- J/ApJ/635/290
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present photometric and kinematic information obtained by measuring 197 planetary nebulae (PNs) discovered in the flattened Fornax elliptical galaxy NGC 1344 (also known as NGC 1340) with an on-band, off-band, and grism+on-band filter technique.
- ID:
- ivo://CDS.VizieR/J/MNRAS/503/2887
- Title:
- PNe angular diameters from SED modeling
- Short Name:
- J/MNRAS/503/2887
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Powerful new, high-resolution, high-sensitivity, multifrequency, wide-field radio surveys such as the Australian Square Kilometre Array Pathfinder (ASKAP) Evolutionary Map of the Universe are emerging. They will offer fresh opportunities to undertake new determinations of useful parameters for various kinds of extended astrophysical phenomena. Here, we consider specific application to angular-size determinations of Planetary Nebulae (PNe) via a new radio continuum spectral energy distribution fitting technique. We show that robust determinations of angular size can be obtained, comparable to the best optical and radio observations but with the potential for consistent application across the population. This includes unresolved and/or heavily obscured PNe that are extremely faint or even non-detectable in the optical.
