J/ApJ/724/748 Galactic anticenter PNe and oxygen abundance (Henry+, 2010)
Abundances of Galactic anticenter planetary nebulae and the oxygen abundance
gradient in the Galactic disk.
Henry R.B.C., Kwitter K.B., Jaskot A.E., Balick B., Morrison M.A.,
Milingo J.B.
<Astrophys. J., 724, 748-761 (2010)>
=2010ApJ...724..748H 2010ApJ...724..748H
ADC_Keywords: Abundances ; Planetary nebulae ; Spectrophotometry ; Milky Way
Keywords: Galaxy: abundances - Galaxy: evolution - ISM: abundances -
planetary nebulae: general
Abstract:
We have obtained spectrophotometric observations of 41 anticenter
planetary nebulae (PNe) located in the disk of the Milky Way. Electron
temperatures and densities, as well as chemical abundances for He, N,
O, Ne, S, Cl, and Ar were determined. Incorporating these results into
our existing database of PN abundances (Henry et al.,
2004AJ....127.2284H 2004AJ....127.2284H, Milingo et al., 2010, Cat. J/ApJ/711/619) yielded
a sample of 124 well-observed objects with homogeneously determined
abundances extending from 0.9 to 21kpc in galactocentric distance. We
performed a detailed regression analysis which accounted for
uncertainties in both oxygen abundances and radial distances in order
to establish the metallicity gradient across the disk to be
12+log(O/H)=(9.09±0.05)-(0.058±0.006)xRg, with Rg in kpc.
While we see some evidence that the gradient steepens at large
galactocentric distances, more objects toward the anticenter need to
be observed in order to confidently establish the true form of the
metallicity gradient.
Description:
Observations of 37 PNe were carried out on the ARC 3.5m telescope at
Apache Point Observatory, NM, using the Dual Imaging Spectrograph
(DIS), during five runs in 2007 between January and November.
We also report new results for four additional PNe (the lattest of
pn.dat file), included in the gradient analysis, observed in 2003 and
2004 with the Kitt Peak National Observatory 2.1m telescope or the
Cerro Tololo Inter-American Observatory (CTIO) 1.5m telescope.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
pn.dat 25 41 Hβ fluxes of each PN (new results)
table2.dat 82 3415 Fluxes and intensities
table3.dat 49 1781 Ionic abundances
table4.dat 66 269 Temperatures and densities
table5.dat 49 564 Total elemental abundances
table6.dat 37 124 Data used in analysis (including previous data)
--------------------------------------------------------------------------------
See also:
J/ApJ/711/619 : α-element abundances in galactic PNe (Milingo+, 2010)
J/ApJ/714/1096 : Galactic planetary nebulae (Stanghellini+, 2010)
J/A+A/494/591 : Abundances in planetary nebulae (Chiappini+, 2009)
J/A+A/500/1089 : Abundances in planetary nebulae (Gorny+, 2009)
J/PAZh/35/574 : He, C, N and O abundances in PNe (Milanova+, 2009)
J/ApJ/689/194 : Distances of galactic planetary nebulae (Stanghellini+, 2008)
J/AZh/82/437 : Calculated chemical composition of galactic PN (Holovatyy+,
2005)
J/A+A/423/199 : Chemical abundances of planetary nebulae (Costa+, 2004)
J/MNRAS/349/793 : Galactic PNe abundances (Perinotto+, 2004)
J/A+A/427/231 : Abundances in planetary nebulae (Gorny+, 2004)
J/A+A/380/300 : Abundances of PN towards Galactic bulge (Escudero+, 2001)
J/A+A/345/629 : Abundance gradients in planetary nebulae (Maciel+, 1999)
J/AJ/115/1989 : Distances of galactic planetary nebulae (Tajitsu+, 1998)
J/A+AS/126/297 : PN abundances (Ratag+ 1997)
J/ApJS/98/659 : Galactic PNe statistical distance scale (Zhang 1995)
J/A+A/282/436 : Abundance gradients from disk PNs (Maciel+ 1994)
J/A+A/280/581 : Chemical abundances of PNe (Pasquali+, 1993)
J/A+AS/94/399 : Absolute fluxes and distances of PN (Cahn+, 1992)
Byte-by-byte Description of file: pn.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- PN Planetary nebula identification
10- 13 F4.2 --- c [0/3.1] Extinction measure c
15- 18 F4.2 --- Ha/Hb Final converged Hα/Hβ line ratio
20- 25 F6.2 [mW/m2] log(FHb) [-14.82/-10.94] Log of the observed Hβ flux
in units of erg/s/cm2
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- PN Planetary nebula identification
10- 39 A30 --- LineID Line identification (1)
41- 46 F6.3 --- f(lam) Reddening function
48- 55 E8.2 --- RFlux ? Raw, uncorrected line flux (Hβ=100) (2)
57- 59 A3 --- f_RFlux Uncertainty flag on RFlux (3)
61- 68 E8.2 --- DFlux ? Dereddened line flux (2)
70- 77 E8.2 --- e_DFlux ? Uncertainty in DFlux (2)
79- 82 A4 --- u_DFlux Uncertainty flag on DFlux (3)
--------------------------------------------------------------------------------
Note (1): An "a" flag after the line identification indicates a deblended line.
Note (2): Scaled to Hβ=100. See pn.dat file for Hβ values.
Note (3): Intensities of strong lines have measurement uncertainties of
≤10%, single colons indicate uncertainties of ≳25%, double
colons indicate uncertainties ≳50%, triple colons indicate
highly suspect measurements, and quadruple colons indicate the
measurement is probably not real.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- PN Planetary nebula identification
10- 21 A12 --- Ion Ion/line(Å) identification, or
"icf" = ionization correction factor
23- 29 A7 --- Met Method used to determine temperature (1)
31 A1 --- f_Abd [*] Indicates Abd included in weighted mean
33- 40 E8.2 [-] Abd ? Derived ionic abundance or icf
42- 49 E8.2 [-] e_Abd ? Uncertainty in Abd
--------------------------------------------------------------------------------
Note (1):
wm = calculated mean value for the ionic abundance weighted by the
observed flux.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- PN Planetary nebula identification
10- 23 A14 --- Param Parameter
25- 32 F8.1 --- Value ? Parameter value (1)
34- 42 F9.2 --- e_Value ? Uncertainty in Value
44- 66 A23 --- n_Value Note on Value (2)
--------------------------------------------------------------------------------
Note (1): Temperatures and densities given in Kelvin and cm-3.
Note (2): If either 5755 or 6584 is unavailable T_[N II]_ is estimated from
T[OIII] (Kwitter & Henry, 2001ApJ...562..804K 2001ApJ...562..804K). Given telluric
effects when calculating T[SIII] if the ratio of 9532/9069 is
≤2.48 then 9532 is used as the nebular transition, if the 9532/9069
ratio is less than 2.48 then 9069 is used. Default T[NII] and
Ne,[ClIII] values and the high density limit for Ne,[SII] are
based on criteria discussed in Kwitter & Henry (2001ApJ...562..804K 2001ApJ...562..804K).
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- PN Planetary nebula identification
10- 13 A4 --- Ratio The 2 elements of the ratio
15- 22 E8.2 --- Abd ? Abundance of Ratio (1)
24- 31 E8.2 --- e_Abd ? Uncertainty in Abd (1)
33- 40 E8.2 --- Solar Asplund et al. (2009ARA&A..47..481A 2009ARA&A..47..481A) solar
abundance ratio (1)
42- 49 E8.2 --- Orion Esteban et al. (2004MNRAS.355..229E 2004MNRAS.355..229E) Orion
abundance ratio (1)
--------------------------------------------------------------------------------
Note (1): All abundances are in linear form.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table6.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- PN Planetary nebula identification
10- 14 F5.2 kpc D Heliocentric distance (1)
16- 20 F5.2 kpc R Galactocentric distance (2)
22- 26 F5.2 kpc DSSV ? Stanghellini et al. 2008, Cat. J/ApJ/689/194,
heliocentric distance
28- 32 F5.2 kpc RSSV ? Stanghellini et al. 2008, Cat. J/ApJ/689/194,
galactocentric distance
34- 37 F4.2 [-] logO/H Oxygen/Hydrogen abundance; 12+log(O/H)
--------------------------------------------------------------------------------
Note (1): Most of the heliocentric distances in this column were taken
directly from Cahn et al. (1992, Cat. J/A+AS/94/399). The sources for
the remaining objects are: H2-18, He2-48, He2-55 (Maciel W.J.,
1984A&AS...55..253M 1984A&AS...55..253M); IC 418 (Guzman et al. 2009AJ....138...46G 2009AJ....138...46G);
M3-15 (Zhang 1995, Cat. J/ApJS/98/659); NGC 6720, NGC 6853, NGC 7293
(Harris H.C. 2006IAUS..234..415H 2006IAUS..234..415H); H3-75 (Amnuel et al.
1984Ap&SS.107...19A 1984Ap&SS.107...19A); K3-64, K3-93 (Jaskot A.E. 2008, Senior thesis,
Williams College); and St3-1 (Tajitsu & Tamura 1998, Cat. J/AJ/115/1989).
Note (2): Computed from the heliocentric distances using the relation:
R={RSun2+[cos(b)*D]2-2*RSun*D*cos(l)*cos(b)}1/2, where R and
D are galactocentric and heliocentric distances, respectively, and b
and l are galactic latitude and longitude, respectively. We assumed
that RSun=8.5kpc.
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 01-Aug-2012