The IUE satellite observatory was used to obtain absolutely-calibrated emission line fluxes for diagnostic lines of multiply-ionized C, N, O, Si, Ne, and Ar which occur in the ultraviolet spectral region of planetary nebulae. These data, when combined with data from the blue, visual, and near infrared, provide improved estimates of ionic concentrations, plasma temperatures and densities, and elemental abundances

Carpenter, K. G.

Czyzak, S. J.

English

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 inal Report
i
(NASA-CH-164986) INTEGRATED FLUXES FOR	 N82-13022
EMISSION LINES IN THE ULTRAVIOLET SPECTRA OF
SEVERAL PLANETARIES Final Report, 15 Apr.
1980
	
30 Jun. 1981 (Ohio State Univ., 	 Unclas
the Cleveland.) 20 p HC A02/MF A01 	 CSCL 03A G3/89 08348
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43212
INTEGRATED FLUXES FOR EMISSION LINES
IN THE ULTRAVIOLET SPECTRA OF SEVERAL PLANETARIES
Kenneth G. Carpenter and Stanley J. Czyzak
Department of Astronomy	 ?.
For the Period
April 15, 1980 - June 30, 1981
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
Goddard Space Flight Center
Greenbelt, Maryland 20771
Grant No. NAG 5-42
November, 1981	
F
Integrated Fluxes for Emission Lines
in the Ultraviolet Spectra of Several Planetaries
f1h^
Kenneth G. Carpenter and S. J. Czyzak
C
	
Department of Astronomy
The Ohio State University
Columbus, Ohio 43210
Abstract
7
The IUE satellite observatory has been used to obtain
absolutely-calibrated emission line fluxes for diagnostic
lines of multiply--ionized C, N. 0, Si, Ne, and Ar which
occur in the ultraviolet spectral region of planetary
nebulae. These data, when combined with data from the
blue, visual, and near infrared, will provide improved
estimates of ionic concentrations, plasma temperatures and
densities, and elemental abundances.
AI. Introduction
F The IUE satellite has made it possible to study diagnostic
lines in the ultraviolet spectral region of nebulae. Since a
number of ions have their strongest lines in the ultraviolet
re-ion observable with the IUE (1150 3200A)p a large number
of lines important in nebular calculations can be studied
with this satellite. These include the following lines# C III]
CA,  1906, 1909) . C IV ( a 1548, 1550)v N III] (A1750). N IV]
( X 1487) . N V ( ^ 1243) . 0 III] 0A 1661. 1666) , 0 IV (h 1403,
1409) 9
 0 V (^ 1371), Si III 0 1892). Ne IV (A 2423, 2425),and
Ar IV (A 2854).
Recent work on a number of nebulae in the blue and visual
regions (Aller and Czyzak, 1979) suggests that an examination
of the ultraviolet spectral region of these nebulae-is
desirable. Also, newer, more accurate ultraviolet transition
probabilities are now available for oxygen and nitrogen ions.
(Czyzak and Krueger, 1979).
We have observed the following six nebulae# J-900, IC 21659
IC 4997 9 NGC 2022 0 NGC 6572, and NGC 7009. The IUE satellite
was used in order to obtain integrated line fluxes for as
many of the diagnostic lines as possible. The observations
obtained and the reduction methods employed to calculate the
line fluxes are detailed in the following section.
r-
is
II. Observations and Data Reduction
A. Observations
Low dispersion spectrograms (resolution n. 6 A) of all
six nebulae were obtained with both the SWP (short-wavelength
prime) and LVIR (long-wavelength redundant) cameras through the
large (10 x 20 aresec oval) entrance aperture. The SWP camera
records the 1150 - 2000 A region and the LOR camera records
the 1700 - 3400 A region, although the later is not very
sensitive below about 1900 A..
Three of the nebula (IC 4997 9 NGC 6572, NGC 7009) were
also observed in both wavelength regions in the high dispersion
echelle mode (resolution about 0.2 A).. Again, the large
entrance aperture was used for all exposures.. The design and
in-flight performance of IUE is described by Boggess et al.
(1978a, 1978b). These data are summarized in Table I which
gives for each exposure the image number, name of the object,
dispersion mode, exposure time, and the date the image was
taken.
A sample of these data are plotted in figures 1-3.
Figures 1 and 2 show the low dispersion spectra of NGC 6572
and IC 2165 for both spectral regions. Note in NGC 05 572 the
strong stellar continuum and the clear P-Cygni profiles of the
Lya a 1215, N V X 1243, 0 V )W71, and C IV ^ 1549 lines.
Aside from the same N V and 0 V lines in NGC 7009, no
I
other P --Gygni profiles are seen in any of the exposures=
3•
the other spectra look much the same as IC 2165, although
rotative line strengths do vary from object to object.
Figure 3 shows a sample of the high resolution data for-NGC
7009. The ratio of the strength of these two lines in the
C III doublet near 1908 A is sensitive to electron density
(Nussbaumer and Schild, 1979). Since they also happen to be
among the strongest lines visible in IUE spectra of planetary
nebula, they are thus a valuable diagnostic aid. However,
their strength can also be a disadvantage= on spectra deep
enough to show a decent number of other lines, these C III
lines are frequently overexposed (as in our NGC 6572 spectrum).
We also note that the apparent feature to the blue side of the
)11906 line is spurious, caused by the proximity of the end of
order 72 on this high dispersion echellogram.
B. Data Reduction
The basic low resolution data were the absolutely-
calibrated, time-integrated spectra provided by the IUE
observatory on the Guest Observer's magnetic tape (the "eslo"
files). Flux values were computed every .25 A t by linear
Interpolation in the original data, to allow more precision
in choosing the wavelength limits for each line integration.
The trapezoid rule was used to perform the integrations. The
resulting numbers were then divided by the exposure time to
obtain absolute fluxes in ergs-cm-2 -see at the earth.
4.
i6'_
The reduction of the high resolution data is less straight-	 f
forward since a standard absolute calibration has not yet been
adopted by the IUE observatory for high resolution images.
In order to present the results on a scale other than the
straight instrumental one, we have elected to use the preliminary
high dispersion, calibration of Cassatella et al. (1981). These
authors define a factor C A = nA /NA # the ratio g at a given
wavelength, of the slit-integrated net IUE Flux Numbers /sec
from low resolution spectra ( n A ) to similarly derived numbers
(NX ) from high resolution spectra. Thus C h Sh -10 where Sh -1
is the inverse sensitivity function for IUE low resolution
spectra, is the inverse sensitivity function for high resolution
spectra. Hence the absolute flux ( erg/cm2/sec/A) = n^ S,j -1
for low resolution data and 	 N x C h Sh -1 for high resolution
data. C^ was determined from comparisons of pairs of low and
high dispersion spectra of the same object, after the resolution
of the high dispersion data had been degraded to that of the
low dispersion data. C A was obtained for both cam^iras for
all wavelengths for continuous sources but Ca could be defined
properly for emission-line spectra only in restricted spectral
regions for each camera, due to a lack of good quality data
outside of these regions. Their equations (7) (C.^ = 228.009
0.0755A)and (8)(C = 167.099 
-0.0229A) are valid for emission line
spectra in the 1400 - 19?5 A region of the SWP camera and the
f	 2300 - 3100 A region of the LWR camera, respectively. The net
r
-r
ripple-corrected spectra ("eshi" files on the Guest Observer
tape) were the basic data for the high resolution analysis. As
in the low-resolution reductions, linear interpolation was
used to define the spectra on a finer wavelength grid ( AA
.01 A is this case) and the trapezoid rule was used to perform.
the integrations. These numbers were then divided by the
exposure time and multiplied by the CA SA -1 listed in Table III.
I	 The CA S ^, -1 are listed in that table to allow the reader to
i
account for any changes which may be made in the high
-resolution
i	 calibration factors assumed here,
III. Results and Discussion
f
The integrated line fluxes for the low and high resolution
spectra along with the proposed identifications of each feature
are presented in Tables II and III, respectively.
The data presented in Table II for low resolution spectra
should be quite reliable. With the high signal/noise ratio in
all these low resolution spectra, good flux measurements were
obtained. The ease of the feature identification process and
the reasonableness of the identifications given indicate a low
probability that any of these are spurious.
The situation for the high resolution data is not quite
as'satisfactory. All these spectra are fairly long exposures
with a low signal/noise ratio over large fractions of the
spectral range. We have tried to insure that only real lines
6.
.a
.f
M
were measured and listed in the table of fluxes, but the
reader should be aware that some of the features measured,
in particular the weaker unidentified features, may not be
real. Unless a question mark appears in the ID column we
feel the identifications given are reliable._ We have noted in
both tables where either partial detector saturation or the
proximity of reseau marks limits the accuracy of the flux
measurements.
The combination of the flux measurements with data from
other wavelength regimes will provide an opportunity to
improve estimates of ionic concentrations, plasma temperature
and densities, and elemental abundances in each of these
planetary nebulae.
Acknowledgements
This work was supported in part by
to The Ohio State University. We thank
the staff of the NE Observatory for th,
Auisition and reduction of these data.
we are grateful for his suggestions and
NASA Grant NAG 5-42
Dr. A. Boggess and
sir assistance in the
To Dr. L. H. Aller
comments.
References
Aller, L. A. and Czyzak, S. J..1979, Astrophy, and Sp. Sci,Ut 397.
Boggess, A. et al. 1978a, Nature, 2M, 372.
. 1978b, Nature,, 377•
J
Cassatella, A., Ponz, D. and Selvelli, P. L. 1981, IUE
Newsletter No, 14,
Czyzak, S. J. and Krueger, T. K. 1979, Astrophys. and Sp.
Sci. 6, 0 0
 99.
Nussbaumer, H. and Schild, H. 1979, Astron. Astrophys. 2..I, L 17.
V {
Table I
Summary of Exposures
Image # Object	 Dispersion Exp. Time Dati Taken
SWP	 8667 IC 4997 L
8668 IC 4997
k
H'
8669 NGC 6572 L
8670 NGC 6572 H-
8676 NGC 2022 L
8677 J-900 L
8678 IC 2165 L
8679 NGC 7009 L
8680 NGC 7009 H
LWR	 7419 IC 4997 L
7420 IC 4997 H
7421 NGC 6572 L
7422 NGC 6572 H.
7424 NGC 7009 H
7428 NGC 2022 L
7429 J-900 L
7430 IC 2165 L
7431 NGC 7009 L
5 min. Apr. 5, 1980
12.0
15
l
120
45 Apr, 6 0 1980
30
20
4 "
20
20 Apr: 50 1980
180
12
120
60
60 Apr. 6, 1980
45
30
8 "
.Table II
Integrated Line Fluxes from Low Re olution Spectra
( units = 1 x 10-12 ergs/cca?/S ac )
Obs. Lab.	 ID	 IC4997 N6572 	 N202a J-900 IC2165 117009
N
f SWP spectra
e	 1242 1243 N V 3. 892 25122
i	 1373 1371 0 V 1.142 6 .212
1399 1406 0 IV 1.07r •992
1486 1486 N IVj 1.931 .848 .720
I
1543 1549 C IV 2.64 56192 10.9 5.39 22.7 6.33
1638 1640 He II 2.57 9078 1.62 6.79 41.7
r	 1662 1663 0 1113 4.07r 2 .36r 2. 86r
k
1719 1.11
1751 1750 N 1113 3.37 3.01 •791 6..25
1904 19.09 C 1I^^ 17.6 a50.0 5.37 8	 8s.7 22.8 2	 .03. ^
LWR spectra
1915 1909 C III] 19.8 50.4 6.72 8.33 21.8 , 3195
2255 2253 He II .566 .507
2301 2297 C III? 4.58
2321 [0 111]
2330 2.16 13.0 1.14 1.54
2323 C III
r
2426 2424 CNe IV] 3.72 .604 2.50 2.,88
2474 2470 CO 113 1.70 6.11
10,
sTable II (continued)
Integrated Line Fluxes from Low Resolution Spectra
(units = 1 x 10'12 ergs/cma/sec)
Obs. Lab. ID	 IC4997 N6572	 N2022 J-900 IC2165 N7009
LWR spectra
'-	 2735	 2733 He II	 ..578	 .594 1.46
2796 Mg II
2.1$s2801
2803 Mg II
r	 2839 2836 0 Iv	 1.49 •179	 9397	 3.31
2948 _	 0743
3027 3023 0 III 2.13
3050 3047 0 III .800	 6.54
3137 3133 0 III	 1.25 2.18	 2.07	 6.11	 30.8
s = contains saturated pixel.
r = contaminated by reseau.
1. Broad, noisy feature unlike any other in this sp4atrum.
r	
2. Measure of emission component of strong P-Cygni profile.
Noted
Lq'( 
is not measured because of the strong geocoronal
contamination.
ll.
.1 Table III
Integrated Line Fluxes SS om High-
 Resolution Spectra
(units • 1 x 10-44 ergo/cm2/sec)
Qua. Lab, ID N6572 IC4997 N7009 Cx 3.%-1
1423.52
.953 3.29
1444.32 .461 3.54
1533.94 .491 4.23
7
E^ 1537.03 .509 4.24
1547.93 1548.2 C IV 1 1 08 1.75 3.14 4.26
i 1549.62 2.35 4.26
1550.42 1550.77 C IV 1.44 1.50 244 4.26
1583.81
.756r 3.94
1590.42 .978 3.87
1639.73 . 814 3.34
►_ 1640.84 164003 He II .439 41,6 3.33
k:
f'
1660.40 1660.80 0 II1] 1.03 1.55 3.13
1663.37 .331 3.10
1665-73 1666.15 0 I111 2.03 3.76 1.74
•
3.06
1718.37 .184 2.55
r
1748.06 1748.61 N I1I] .471 .280 2.28
1749.21 1749.67 N III-] 1.39 1.21 1.53 2.27
r 1751.61 1752.16 N III] .882 .635 2o24
1757.47 .296 2.21
r
1795.51 .-375 .258 0695 1.95
1796.43 001 .349 1.95
r
1810.27 .270 1.90
E
1814.22 .2.57 1189
1882. 55 .332rr 1.75
12.
Table III (continued)
Integrated Line Fluxes from High Resolution
a Spectra.
Lab. D X6572 IC4997 N7009 CON 	
1
T
1884.00 .192 .312R4 1.75
1888.61 .726 1.74
1891.53 1892.03 Si III .392 .428 1.73
1906.30 1906.68 C 111 23.93 1.25 18,6 1.71
r	 1908.43 1908.73 C III] 23.98 20.33 12.2 1.70
2320.31 2320.95 CO LII] .649 . 703 1.06
2323.55 2323.50 C II] ' l,46 1.04
2324.44 2324.69 C II] .762 1.04
2325.28 2325.40 C II] ' 4.29 .653 1.04
2326.29 2326.93 C 111 :2.58 .334 1.03
2327.93 2328.12 C II] .684 1.02'
2421.65 N IV
2421.28 1.34 .723
2422.60 [Ne IV]
2423.91 2425.24 [Ne IV] 1.45 .715
2469.75 2470.30 CO II] 5.52' 1.52 .608
r
2510.73 2511.21 He II 1.34 .537
2517. 43 - .121r .529
_	 2655.22 0367 .367
2663.10 .158 .381
2691.58 .218 .362
2695,91 .257 .36o
2722.99
.365 .351
2732.77 2733.30 He II 1.82 .348
13.
w
Table III (continued)
Integrated Line Fluxes from High Kesolut or
Spectra
bs. Lab. ID	 N6572 IC4997
	
N7009 1C^ S;
2745.20
.316 .345
2759.44 .086 .343
2763.20 .387 .115 .343
2775.75 .172Ra 0341
J 2785.04 .075 1341
I 2793.08 .091 .0:59 .340
2794.73 ` .198 .130 .339
j 2795.52 Mg II
2795.98 .314 •339
2801.96 ..126 .930
.339
2802. .70 Mg II
2803.10 6215
.339	 a
. 2807.84 .286 040
2811.12 0137 .340
2828.63 2829.16 0 IV? .547 0225 .,674 ,342
2835.79 2836.26 0 IV 3.32 043
2853.13 2853.64 CAr IV] .252 .345 .511
.345
2858.75 28S9.16 N V? .463
.348	 1
2900.80 •177 .302 .369	 ti
2921.22 2921.45 0 IV? .074 .386	 $
2942.08 .123 .403
2944.69 1.52 *775 .406
:- 2972 . 19 2972 . 56 N III? . 102 0439
2980.64
.132 .451}.
3010.79
.097 .500
14.
Y
j
Table III (continued)
Integrated Line Fluxes from High Resolution
Spectra
Obs.	 Lab.	 ID	 N6572 IC4997 N7009	 C.A Sa 1
dt
3022.91	 3023.45	 0 III	 1.25	 .527
3024.47.	 .152	 .540
i
3046.69	 3047.13	 0 Zii	 3.23r	 .580
I	 3066.77
	 `329	 .666
i
3132.37
	
3132.86	 0 III	 22.:5r	 1.081
3202.50	 3203.10	 He II	 5.75	 2.031
a
'	 r	 reseau
RQ = reality questionable
1 Accuracy of calibration uncertain at these wavelengths.
Notes
1. Features shortward of .1400 % are not included in this
r
	
	
table since the absolute-calibration is not defined
	 a
at those wavelengths for high resolution emission-
line spectra.
2. Data from lines below 2000 A are from the SWP camera
i	 while data from lines above 2000 A are from the LWR
camera*
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Figure Captions
Figure 1.
Low resolution spectra of the planetary nebulae NGC 6572
and IC 2165, taken through the large aperture with the SWP
cameras The C III] feature at 1908 A is saturated in NGC 65720
Figure 2.
Low resolution spectra of the planetary nebulae NGC 6572
and IC 2165, taken through the large aperature with the LWR
camera. The small "x" • s indicate that the feature at 2200 A
in both spectra is not real but results from a permanent "hot
spot" on the detector surface.
Figure 3.
The C IITJ doublet near 1908 A in the high dispersion SWP
spectrum of NGC 7009, The feature blueward of the 1906 line is
not real but is an edge-of-order effect.


Integrated fluxes for emission lines in the ultraviolet spectra of several planetaries

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