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Selected highlights from the Extreme Ultraviolet Explorer
Ah. Space R.s. Vol. 16. No. 3, pp. (3)25-(3)28, 1995 Copyright 0 1995 CCSPAR Printed in Great Btitaio. All ti ts reserved. 0273-I 177195@$9.50 + 0.00 0273-I
177(95)@039-9
SELECTED HIGHLIGHTS FROM THE EXTREME ULTRAVIOLET EXPLORER S. Bowyer and R. F. Malina Centerfor EUV Astrophysics, 21.50 K&edge Berkeley, CA 94720-5030, U.S.A.
Street, University of California,
ABSTRACT We present a few scientific highlights from the Extreme Ultraviolet Explorer (EWE) all-sky and deep surveys, from the EWE Right Angle Program, and from the EWE Guest Observer Program, The First EUVE Source Catalog /I/ includes 410 extreme ultraviolet (EUV) sources detected in the initial processing of the EUVE all-sky data. A program of optical identification indicates that counterparts include cool star coronae, flare stars, hot white dwarfs, central stars of planetary nebulae, B star photospheres and winds, an X-ray binary, extragalactic objects (active galactic nuclei, BL Lacertae), solar system objects (Moon, Mars, IO), supernova remnants, and two novae. INTRODUCTION The Extreme Ultraviolet Explorer was designed to carry out all-sky surveys in four separate wavebands covering the entire EUV bandpass. These four bands were roughly centered at 100, 200, 400, and 600 A 121. The second EUVE
source catalog is now under development. This catalog will include sources from the approximately 20% of the sky missed in the first six months due to breaks to carry out calibrations, and it will include new sources found using improved detection techniques. Upwards of 600 sources are expected to be reported in this catalog. A breakdown of the numbers and classes of objects currently identified are provided in Table 1. DISCUSSION The variety of objects detected has been surprisingly large, and the number of sources in some of the more exotic categories is far larger than expected. In Table 2 we list 23 extragalactic objects detected by EUVE. Some qualifications have to be made in regards to this list, but the vast majority of these identifications are certainly valid. The source EUVE 50425-572 has two possible candidates in the field: the extragalactic source 1H 0419-577 and a 15’h magnitude blue object. Further work will be required to establish with certainty which of these objects is the source of the EUV emission. Arguments in favor of the source being extragalactic include the fact that the Galactic hydrogen column in this direction is appropriately low (-2 x 102’) and the X-ray-to-EUV flux is about the same as that for many of the other extragalactic sources detected in the EUV. The classification of this object in uncertain. Brissenden /3/ classifies the source as a quasi-stellar object based on optical data while Marshall /4/ classifies it as a Seyfert on unstated grounds. Neutron stars are a second class of object whose detection with EUVE is surprising. In Table 3 we list the neutron stars detected to date. Hercules X-l is a binary system; the EUV emission appears to emanate from material heated by accretion. Pulses have not been observed, but the limits are not particularly restrictive (525%). The remaining five objects are classic pulsars (although it may be argued Geminga is in a class by itself). Pulsed EUV emission has not yet been reported but the upper limits on a pulsed fraction are not particularly definitive. Unfortunately, the EUVE data acquisition mode JASR 16:3-C
(3125
S. Howyer and R. F. Maha
TABLE 1 Second EWE
Catalog: Partial List of Objects Detected Object Type
Number
Late-type stars (F, G, K, M) White dwarfs Early-type stars (0, B, A) Cataclysmic variables Planetary nebulae Neutron stars Novae Active galactic nuclei Supernova remnants Solar system objects No identification
TABLE 2 NAME EUVE EUVE EUVE EUVE EUVE EUVE EUVE EUVE EUVE EUVE EUVE EUVE EUVE EUVE EUVE EUVE EUVE EUVE EUVE EUVE EUVE EUVE EUVE
221 106 24 1.5 7 6 2 23 2 3 123
Extragalactic EVVE Sources RA2000 hms
JO425-572 04 25 50 J10151494 10 15 04 J 1034+396 10 34 36 J 1104+382 11 04 33 11 14 39 J1114+406 J1119+213 11 19 08 J 1203+445 12 03 10 J 1229+020 12 29 07 J 1236-t-456 12 36 49 J 1352+692 13 52 56 14 17 01 J1417+449 14 17 59 J1417+251 14 21 30 J1421+477 J 1428+426 14 28 33 J 1442+354 14 42 08 15 56 42 J 15X+452 16 17 42 Jl617+323 J 1653+397 16 53 52 J2132+101 21 32 31 21 58 51 52 158-302 52209-47 1 22 09 17 23 43 32 J2343-149 52359-306 23 59 08
Dec2000 dm
1OOA
-57 +49 +39 +38 +40 +21 i44 +02 +45 +69 +44 +25 +47 +42 +35 +45 +32 +39 +lO -30 -47 -14 -30
34.0 28.1 9.3 56.0 1.4 17.0 19.3 79.2 2.4 33.0 5.2 23.6 3.4 32.7 56.0 4.3 3.5 30.0 2.0 297.0 23.0 3.0* 14.7
12.8 26.0 38.0 12.6 37.0 19.6 31.9 03.1 38.9 17.6 56.0 08.2 47.0 40.4 27.7 13.9 22.9 45.0 07.9 13.6 10.0 55.8 37.7
elks
ID Name
Type
Ref
1H 0419-577 lH1013+498 RE J1034+393 Mrk 42 1 3C 254 PG 1116+215 NGC 405 1 3C 273 CGCG 244-033 Mrk 279 PG 1415+451 NGC 5548 CG0912 H 1426+427 Mrk 478 MS 1555.14522 3C 332 Mrk 501 Mrk 1513 PKS 2 155-304 NGC 7213 1E 2340.9-1511 1H 2354-315
Seyfert BL Lac Seyfert BL Lac
HM HM HM B L L HM HM L B L HM L B HM L L B KM B HM KM KM
QSO QSO Seyfert
QSO AGN Seyfert
QSO Seyfert
QSO BL Lac Seyfert AGN Seyfert BL Lac Seyfert BL Lac Seyfert Seyfert BL Lac
Note: * = Count rate from Deep Survey Telescope. References: HM = 141;B = Ill; L = 151;and KM = 161. designed to provide high time resolution was not employed in these observations making it difficult (though still entirely possible) to obtain this information. The EWE high time resolution mode will be employed in all future observations of neutron stars. A final class of object originally not expected to be detected in the EUV is the central stars of planetary nebula. The typically large distances to these objects and the expected self-absorption provided a discouraging scenario. Four planetary nebula were detected in the EUV with the ROSAT Wide Field Camera /12,13/. Seven planetary nebula were detected by EWE 1141; these are listed in Table 4.
(3)27
Highlights from the Extreme Ullraviolcr E.xpkmr
TABLE 3
Neutron Stars Detected with EWE
Object
DS*
JO43747 15 BO655+64 BO656+14 B0943+10 Geminga Her X-l
0.038
Age
DM
d
Ref.
5 x lo9 4 x IO9 1 x lo5 6 x lo6 5x lo5 < IO7
2.6 8.8 14.0 15.4
140 480 760 980 <500 5000
EFB E FOE E H v
LX .013
0.024 .018 0.02 0.18
*Notes: DS = counts s-’ EWE Deep Survey; LX = counts SC’EWE Age = years; DM = cm-3 pc; and d = distance in pc.
Lexan Sky-Survey;
References: EFB = /7/; E = /8/; FOE = /9/; H = /lo/; and V = /I l/.
TABLE 4
Planetary Nebula Detected with EWE Name
PN G094.0e27.4 PN G118.8-74.7 PN G148.4+57.0 PN G220.3-53.9 PN G294.1+43.6 PN G339.9+88.4 NGC6853
Other Name K 1-16 NGC 246 NGC 3587 NGC 1360 NGC 4361 LoTr 5 Dumbell
Lex/B (counts s-‘) 0.016 0.114 0.024 0.140 0.033 0.055 0.060
err (counts s-‘) 0.002 0.016 0.008 0.015 0.010 0.014 0.010
The current primary data acquisition mode utilizes the three spectrometers on EUVE. These spectrometers are based on a novel variable time grating /15/ provide spectra from roughly 70 to 760 A with a resolution (h/Ah) of roughly 300. (This is more than an order of magnitude better than the highest spectral resolution detectors on the ASCI satellite.) NASA has offered the use of these spectrometers to guest observers worldwide. A wide variety of studies have been carried out with this instrumentation and these results are now appearing in the open literature. This work is supported by NASA contracts NAS5-30180 and NAS5-29298 REFERENCES 1.
S. Bowyer, R. Lieu, M. Lampton, J. Lewis, X. Wu, J. J. Drake, and R. F. Malina, The First EUVE Source Catalog, Ap. J. Supp., 93 (2), 569, (1994).
2.
S. Bowyer and R. F. Malina, The EUVE Mission, in Extreme Ultraviolet Astronomy, ed. R. F. Malina and S. Bowyer, New York: Pergamon Press, pp. 397-408, (1991).
3.
R. J. V. Brissenden, private communication, (1994).
4
H.L. Marshall, A. Fruscione, and T.E. Carone, Active Galaxies Observed during the Extreme Ultraviolet Explorer All-Sky Survey, Ap. J., (1995) in press.
5.
R. Lieu, J. Mittaz, S. Bowyer, J. Lewis, and C.-Y. Hwang, EUV Emission from a Sample of Active Galactic Nuclei, Adv. Space Res., this issue.
(928
s. Rowyer and R. F. MAina
6.
K. McDonald, N. Craig, M. M. Sirk, J. J. Drake, A. Fruscione, J. V. Vallerga, and R. F. Malina, Serendipitous EUV Sources Detected during the First Year of the Extreme Ultraviolet Explorer Right Angle Program, Aeon. J., (1994) in press.
7.
J. Edelstein, R. S. Foster, and S. Bowyer, 184th AAS Bulletin, 1994.
8.
J. Edelstein, HEAD Bulletin of abstracts, 1994.
9.
J. P. Finley, H. Ogelman, and J. Edelstein, 184th AAS Bulletin, 1994.
10.
J. Halpem, private communication, (1994)
11.
Vrtilek, S. D., et al., Ap. J. Len., 1994, in press.
12.
K. A. Pounds, et al., MNRAS, 260, 77, (1993).
13.
M. G. Hoare, M. A. Barstow, K. Werner, and T. A. Fleming, MNRAS, (1994) submitted.
14.
A. Fruscione, J. J. Drake, K. McDonald, and R.F. Malina, A Volume-Limited Survey of High Galactic Latitude Planetary Nebulae with the Extreme Ultraviolet Explorer, Ap. J., (1995) in press.
15.
M.C. Hettrick and S. Bowyer, Variable Line-Space Gratings: New Designs for Use in Grazing Incidence Spectrometers, Appl. Opt., 22, 3921-3924, (1983).
177(95)@039-9
SELECTED HIGHLIGHTS FROM THE EXTREME ULTRAVIOLET EXPLORER S. Bowyer and R. F. Malina Centerfor EUV Astrophysics, 21.50 K&edge Berkeley, CA 94720-5030, U.S.A.
Street, University of California,
ABSTRACT We present a few scientific highlights from the Extreme Ultraviolet Explorer (EWE) all-sky and deep surveys, from the EWE Right Angle Program, and from the EWE Guest Observer Program, The First EUVE Source Catalog /I/ includes 410 extreme ultraviolet (EUV) sources detected in the initial processing of the EUVE all-sky data. A program of optical identification indicates that counterparts include cool star coronae, flare stars, hot white dwarfs, central stars of planetary nebulae, B star photospheres and winds, an X-ray binary, extragalactic objects (active galactic nuclei, BL Lacertae), solar system objects (Moon, Mars, IO), supernova remnants, and two novae. INTRODUCTION The Extreme Ultraviolet Explorer was designed to carry out all-sky surveys in four separate wavebands covering the entire EUV bandpass. These four bands were roughly centered at 100, 200, 400, and 600 A 121. The second EUVE
source catalog is now under development. This catalog will include sources from the approximately 20% of the sky missed in the first six months due to breaks to carry out calibrations, and it will include new sources found using improved detection techniques. Upwards of 600 sources are expected to be reported in this catalog. A breakdown of the numbers and classes of objects currently identified are provided in Table 1. DISCUSSION The variety of objects detected has been surprisingly large, and the number of sources in some of the more exotic categories is far larger than expected. In Table 2 we list 23 extragalactic objects detected by EUVE. Some qualifications have to be made in regards to this list, but the vast majority of these identifications are certainly valid. The source EUVE 50425-572 has two possible candidates in the field: the extragalactic source 1H 0419-577 and a 15’h magnitude blue object. Further work will be required to establish with certainty which of these objects is the source of the EUV emission. Arguments in favor of the source being extragalactic include the fact that the Galactic hydrogen column in this direction is appropriately low (-2 x 102’) and the X-ray-to-EUV flux is about the same as that for many of the other extragalactic sources detected in the EUV. The classification of this object in uncertain. Brissenden /3/ classifies the source as a quasi-stellar object based on optical data while Marshall /4/ classifies it as a Seyfert on unstated grounds. Neutron stars are a second class of object whose detection with EUVE is surprising. In Table 3 we list the neutron stars detected to date. Hercules X-l is a binary system; the EUV emission appears to emanate from material heated by accretion. Pulses have not been observed, but the limits are not particularly restrictive (525%). The remaining five objects are classic pulsars (although it may be argued Geminga is in a class by itself). Pulsed EUV emission has not yet been reported but the upper limits on a pulsed fraction are not particularly definitive. Unfortunately, the EUVE data acquisition mode JASR 16:3-C
(3125
S. Howyer and R. F. Maha
TABLE 1 Second EWE
Catalog: Partial List of Objects Detected Object Type
Number
Late-type stars (F, G, K, M) White dwarfs Early-type stars (0, B, A) Cataclysmic variables Planetary nebulae Neutron stars Novae Active galactic nuclei Supernova remnants Solar system objects No identification
TABLE 2 NAME EUVE EUVE EUVE EUVE EUVE EUVE EUVE EUVE EUVE EUVE EUVE EUVE EUVE EUVE EUVE EUVE EUVE EUVE EUVE EUVE EUVE EUVE EUVE
221 106 24 1.5 7 6 2 23 2 3 123
Extragalactic EVVE Sources RA2000 hms
JO425-572 04 25 50 J10151494 10 15 04 J 1034+396 10 34 36 J 1104+382 11 04 33 11 14 39 J1114+406 J1119+213 11 19 08 J 1203+445 12 03 10 J 1229+020 12 29 07 J 1236-t-456 12 36 49 J 1352+692 13 52 56 14 17 01 J1417+449 14 17 59 J1417+251 14 21 30 J1421+477 J 1428+426 14 28 33 J 1442+354 14 42 08 15 56 42 J 15X+452 16 17 42 Jl617+323 J 1653+397 16 53 52 J2132+101 21 32 31 21 58 51 52 158-302 52209-47 1 22 09 17 23 43 32 J2343-149 52359-306 23 59 08
Dec2000 dm
1OOA
-57 +49 +39 +38 +40 +21 i44 +02 +45 +69 +44 +25 +47 +42 +35 +45 +32 +39 +lO -30 -47 -14 -30
34.0 28.1 9.3 56.0 1.4 17.0 19.3 79.2 2.4 33.0 5.2 23.6 3.4 32.7 56.0 4.3 3.5 30.0 2.0 297.0 23.0 3.0* 14.7
12.8 26.0 38.0 12.6 37.0 19.6 31.9 03.1 38.9 17.6 56.0 08.2 47.0 40.4 27.7 13.9 22.9 45.0 07.9 13.6 10.0 55.8 37.7
elks
ID Name
Type
Ref
1H 0419-577 lH1013+498 RE J1034+393 Mrk 42 1 3C 254 PG 1116+215 NGC 405 1 3C 273 CGCG 244-033 Mrk 279 PG 1415+451 NGC 5548 CG0912 H 1426+427 Mrk 478 MS 1555.14522 3C 332 Mrk 501 Mrk 1513 PKS 2 155-304 NGC 7213 1E 2340.9-1511 1H 2354-315
Seyfert BL Lac Seyfert BL Lac
HM HM HM B L L HM HM L B L HM L B HM L L B KM B HM KM KM
QSO QSO Seyfert
QSO AGN Seyfert
QSO Seyfert
QSO BL Lac Seyfert AGN Seyfert BL Lac Seyfert BL Lac Seyfert Seyfert BL Lac
Note: * = Count rate from Deep Survey Telescope. References: HM = 141;B = Ill; L = 151;and KM = 161. designed to provide high time resolution was not employed in these observations making it difficult (though still entirely possible) to obtain this information. The EWE high time resolution mode will be employed in all future observations of neutron stars. A final class of object originally not expected to be detected in the EUV is the central stars of planetary nebula. The typically large distances to these objects and the expected self-absorption provided a discouraging scenario. Four planetary nebula were detected in the EUV with the ROSAT Wide Field Camera /12,13/. Seven planetary nebula were detected by EWE 1141; these are listed in Table 4.
(3)27
Highlights from the Extreme Ullraviolcr E.xpkmr
TABLE 3
Neutron Stars Detected with EWE
Object
DS*
JO43747 15 BO655+64 BO656+14 B0943+10 Geminga Her X-l
0.038
Age
DM
d
Ref.
5 x lo9 4 x IO9 1 x lo5 6 x lo6 5x lo5 < IO7
2.6 8.8 14.0 15.4
140 480 760 980 <500 5000
EFB E FOE E H v
LX .013
0.024 .018 0.02 0.18
*Notes: DS = counts s-’ EWE Deep Survey; LX = counts SC’EWE Age = years; DM = cm-3 pc; and d = distance in pc.
Lexan Sky-Survey;
References: EFB = /7/; E = /8/; FOE = /9/; H = /lo/; and V = /I l/.
TABLE 4
Planetary Nebula Detected with EWE Name
PN G094.0e27.4 PN G118.8-74.7 PN G148.4+57.0 PN G220.3-53.9 PN G294.1+43.6 PN G339.9+88.4 NGC6853
Other Name K 1-16 NGC 246 NGC 3587 NGC 1360 NGC 4361 LoTr 5 Dumbell
Lex/B (counts s-‘) 0.016 0.114 0.024 0.140 0.033 0.055 0.060
err (counts s-‘) 0.002 0.016 0.008 0.015 0.010 0.014 0.010
The current primary data acquisition mode utilizes the three spectrometers on EUVE. These spectrometers are based on a novel variable time grating /15/ provide spectra from roughly 70 to 760 A with a resolution (h/Ah) of roughly 300. (This is more than an order of magnitude better than the highest spectral resolution detectors on the ASCI satellite.) NASA has offered the use of these spectrometers to guest observers worldwide. A wide variety of studies have been carried out with this instrumentation and these results are now appearing in the open literature. This work is supported by NASA contracts NAS5-30180 and NAS5-29298 REFERENCES 1.
S. Bowyer, R. Lieu, M. Lampton, J. Lewis, X. Wu, J. J. Drake, and R. F. Malina, The First EUVE Source Catalog, Ap. J. Supp., 93 (2), 569, (1994).
2.
S. Bowyer and R. F. Malina, The EUVE Mission, in Extreme Ultraviolet Astronomy, ed. R. F. Malina and S. Bowyer, New York: Pergamon Press, pp. 397-408, (1991).
3.
R. J. V. Brissenden, private communication, (1994).
4
H.L. Marshall, A. Fruscione, and T.E. Carone, Active Galaxies Observed during the Extreme Ultraviolet Explorer All-Sky Survey, Ap. J., (1995) in press.
5.
R. Lieu, J. Mittaz, S. Bowyer, J. Lewis, and C.-Y. Hwang, EUV Emission from a Sample of Active Galactic Nuclei, Adv. Space Res., this issue.
(928
s. Rowyer and R. F. MAina
6.
K. McDonald, N. Craig, M. M. Sirk, J. J. Drake, A. Fruscione, J. V. Vallerga, and R. F. Malina, Serendipitous EUV Sources Detected during the First Year of the Extreme Ultraviolet Explorer Right Angle Program, Aeon. J., (1994) in press.
7.
J. Edelstein, R. S. Foster, and S. Bowyer, 184th AAS Bulletin, 1994.
8.
J. Edelstein, HEAD Bulletin of abstracts, 1994.
9.
J. P. Finley, H. Ogelman, and J. Edelstein, 184th AAS Bulletin, 1994.
10.
J. Halpem, private communication, (1994)
11.
Vrtilek, S. D., et al., Ap. J. Len., 1994, in press.
12.
K. A. Pounds, et al., MNRAS, 260, 77, (1993).
13.
M. G. Hoare, M. A. Barstow, K. Werner, and T. A. Fleming, MNRAS, (1994) submitted.
14.
A. Fruscione, J. J. Drake, K. McDonald, and R.F. Malina, A Volume-Limited Survey of High Galactic Latitude Planetary Nebulae with the Extreme Ultraviolet Explorer, Ap. J., (1995) in press.
15.
M.C. Hettrick and S. Bowyer, Variable Line-Space Gratings: New Designs for Use in Grazing Incidence Spectrometers, Appl. Opt., 22, 3921-3924, (1983).