J/ApJS/149/29 ROSAT North Ecliptic Pole Survey (Gioia+, 2003)

J/ApJS/149/29/notes.dat Individual notes (346 records)


RX
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RXJ1716.2+6836Also called RX J1716.0+6836 in Boller et al.
RXJ1716.2+6836 (1997MNRAS.289..393B). The identification comes from the
RXJ1716.2+6836 revised Burbidge catalog (Hewitt & Burbidge, Cat. VII/158,
RXJ1716.2+6836 1993ApJS...87..451H).
RXJ1717.7+6431There is a star within the error circle that is closer to the
RXJ1717.7+6431 X-ray position (7.7") than the AGN2. We still believe that the
RXJ1717.7+6431 AGN2 is the correct identification, not only because it is an
RXJ1717.7+6431 AGN but also because it appears to be in a distorted spiral in
RXJ1717.7+6431 our UH 2.2m B-band image. Distortion implies some kind of
RXJ1717.7+6431 interaction and often these distorted galaxies are X-ray
RXJ1717.7+6431 sources.
RXJ1719.8+6457This source is one of two sources in the NEP still unidentified.
RXJ1719.8+6457 Optical spectra were taken for seven objects within 80" from
RXJ1719.8+6457 the X-ray position, but no plausible identification was found.
RXJ1720.8+6210There are two galaxies at the same redshift as the AGN1
RXJ1720.8+6210 (z=0.7313) and closer to the X-ray centroid (approximate
RXJ1720.8+6210 positions from DSS-2 red are for cfh 11,
RXJ1720.8+6210 RA_2000_ = 17 20 46.8, DE_2000_ = +62 10 25; and for cfh 12b,
RXJ1720.8+6210 RA_2000_ = 17 20 43.9, DE_2000_ = +62 10 11). We still identify
RXJ1720.8+6210 the source as AGN1 since its spectrum shows a broad Mg II
RXJ1720.8+6210 emission line (FWHM>4000km/s). However, the presence of a
RXJ1720.8+6210 distant cluster at z~0.73 is not excluded.
RXJ1723.1+6826This source is identified with a QSO (RA_2000_ = 17 23 09.9,
RXJ1723.1+6826 DE_2000_ = +68 26 56;, z=0.9782+/-0.001) that is 4" away from
RXJ1723.1+6826 the X-ray centroid. The optical spcetrum shows a very broad
RXJ1723.1+6826 Mg II emission line (FWHM>=7000km/s). A second object at
RXJ1723.1+6826 RA_2000_ = 17 23 10.1, DE_2000_ = +68 26 51, just south of the
RXJ1723.1+6826 QSO and only 3.4" away from the X-ray centroid, has a similar
RXJ1723.1+6826 redshift (z=0.9777) as the QSO. This second object is fainter
RXJ1723.1+6826 and has a narrower Mg II line in emission. Both objects could
RXJ1723.1+6826 contribute to the X-ray emission even if we indicate the object
RXJ1723.1+6826 with broader Mg II line as the identification in the table.
RXJ1724.1+7000and RX J1724.2+6956 These two sources were identified as a group
RXJ1724.1+7000 of galaxies in Henry et al. (1995ApJ...449..422H). The X-ray
RXJ1724.1+7000 morphology is complex and elongated along the north-south
RXJ1724.1+7000 direction (see Fig. 1a in Henry et al.. 1995ApJ...449..422H).
RXJ1724.1+7000 We confirm here the identification of these sources with a
RXJ1724.1+7000 single group of galaxies at z=0.0386.
RXJ1724.2+6956See RX J1724.1+7000.
RXJ1727.0+6926A radio source (0.96+/-0.06mJy at 6cm) was detected with the VLA
RXJ1727.0+6926 in the DnC array at the position of the optical counterpart by
RXJ1727.0+6926 T. Rector (2003, private communication).
RXJ1727.8+6748There are several galaxies in the area for which no optical
RXJ1727.8+6748 spectrum is available. The suggested identification is the AGN1
RXJ1727.8+6748 at z=0.4950 (RA_2000_ = 17 27 45.5, DE_2000_ = +67 48 43) lying
RXJ1727.8+6748 22" away from the X-ray centroid, with a broad (FWHM>7000km/s)
RXJ1727.8+6748 Mg II emission line in its optical spectrum.
RXJ1732.5+7031This object appears in the sample of identified northern ROSAT
RXJ1732.5+7031 sources by Appenzeller et al. (1998ApJS..117..319A) with a
RXJ1732.5+7031 redshift z=0.209 versus our z=0.2114.
RXJ1732.9+6533The redshift for this QSO (z=0.8560) comes from Hewitt &
RXJ1732.9+6533 Burbidge (Cat. VII/158, 1993ApJS...87..451H).
RXJ1736.3+6802This group of galaxies was published in Henry et al.
RXJ1736.3+6802 (1995ApJ...449..422H). There are 12 galaxies with spectroscopic
RXJ1736.3+6802 redshifts. Refer to Henry et al. (1995ApJ...449..422H) for more
RXJ1736.3+6802 details and for an X-ray contour image (their Fig. 1c).
RXJ1736.9+6845This X-ray source is MS 1737.2+6847 and its identification with
RXJ1736.9+6845 SAO17576 ({omega} Draconis) comes from the EMSS; see Stocke et
RXJ1736.9+6845 al. (1991ApJS...76..813S) and Maccacaro et al.
RXJ1736.9+6845 (1994ApL....29..267M).
RXJ1736.4+6820The X-ray source is identified with GAT 732, a star with an E
RXJ1736.4+6820 magnitude in APM of 8.98. The star has a high proper motion
RXJ1736.4+6820 (about 1' in 50yr).
RXJ1739.7+6710This source is MS 1739.8+6712 and is identified as AGN1. The
RXJ1739.7+6710 redshift, z=0.118, comes from Stocke et al.
RXJ1739.7+6710 (1991ApJS...76..813S); an optical finding chart is published in
RXJ1739.7+6710 Maccacaro et al. (1994ApL....29..267M).
RXJ1741.2+6507There is a cluster candidate in the field of this source
RXJ1741.2+6507 identified as AGN1 at z=0.7466. We have concordant redshifts
RXJ1741.2+6507 for two galaxies (A and B):
RXJ1741.2+6507 RA_2000_ = 17 41 15.5, DE_2000_ = +65 07 53, z_A_=0.3797;
RXJ1741.2+6507 RA_2000_ = 17 41 07.7, DE_2000_ = +65 07 47, z_B_=0.3775.
RXJ1743.4+6341This cluster, associated with A2280, has a large gravitational
RXJ1743.4+6341 arc that is described in Gioia et al. (1995A&A...297L..75G).
RXJ1745.2+6556In the field of this source, identified as a cluster of galaxies
RXJ1745.2+6556 at z=0.6080+/-0.0005 (optical spectrum for a member galaxy is
RXJ1745.2+6556 shown in Fig. 10) there is also an AGN (RA_2000_ = 17 45 17.6,
RXJ1745.2+6556 DE_2000_ = +65 56 02, z=0.2904) that is ~18" away from the
RXJ1745.2+6556 X-ray centroid. The AGN could contribute to the X-ray emission
RXJ1745.2+6556 of the source. However, it is difficult to classify the AGN as
RXJ1745.2+6556 type 1 or type 2 since there is no H{beta} emission line, and
RXJ1745.2+6556 the H{alpha} emission line is blended with N II. The spectrum
RXJ1745.2+6556 of the AGN has a very red continuum.
RXJ1746.1+6737The identification of this X-ray source comes from the EMSS.
RXJ1746.1+6737 This is MS 1746.2+6738 identified as AGN1 at z=0.041 by Stocke
RXJ1746.1+6737 et al. (1991ApJS...76..813S). The AGN1 (RA_2000_ = 17 46 08.8,
RXJ1746.1+6737 DE_2000_ = +67 37 15) is 25" south of a bright SAO star
RXJ1746.1+6737 (SAO17632, RA_2000_ = 17 46 08.7, DE_2000_ = +67 37 43,
RXJ1746.1+6737 m_V_=7.79), which could also contribute to the X-ray emission.
RXJ1746.2+6227The redshift for this QSO (z=3.889) is taken from Hook et al.
RXJ1746.2+6227 (1995MNRAS.273L..63H; see their Fig. 2 for a spectrum). Stickel
RXJ1746.2+6227 (1993A&A...275...49S) gives a redshift of z=3.886 for this
RXJ1746.2+6227 object. The QSO was independently discovered as an X-ray source
RXJ1746.2+6227 by Becker, Helfand, & White (1992AJ....104..531B), who measured
RXJ1746.2+6227 a redshift of z=3.87 (optical spectrum in their Fig. 2). An
RXJ1746.2+6227 X-ray spectrum with ASCA is published in Figure 1 of Kubo et
RXJ1746.2+6227 al. (1997MNRAS.287..328K).
RXJ1747.0+6836This very bright source is MS 1747.2+6837. The identification as
RXJ1747.0+6836 AGN1 (z=0.063) comes from Kriss & Canizares
RXJ1747.0+6836 (1982ApJ...261...51K) and Stocke et al. (1991ApJS...76..813S).
RXJ1747.0+6836 P. F. Winkler (1982, private communication) originally
RXJ1747.0+6836 discovered this object.
RXJ1747.4+6626There are two objects here, both AGN1 and at the same redshift
RXJ1747.4+6626 (z=0.1391), which could both contribute to the X-ray emission.
RXJ1747.4+6626 The optical position for one of them is RA_2000_ = 17 27 47.0,
RXJ1747.4+6626 DE_2000_ = +66 26 24 (given in Table 3). The second object,
RXJ1747.4+6626 which is a spiral galaxy at z=0.1390, is at
RXJ1747.4+6626 RA_2000_ = 17 47 26.6, DE_2000_ = +66 26 05.
RXJ1747.9+6623We identify this source as a normal galaxy (GAL), but there are
RXJ1747.9+6623 two objects possibly interacting. Object A
RXJ1747.9+6623 (RA_2000_ = 17 47 58.5, DE_2000_ = +66 23 26, z=0.1739) is a
RXJ1747.9+6623 narrow emission-line galaxy with H{alpha}, H{beta}, H{gamma},
RXJ1747.9+6623 and [O III] emission lines in the optical spectrum and shows
RXJ1747.9+6623 the morphology of a disturbed spiral. Object B
RXJ1747.9+6623 (RA_2000_ = 17 47 56.8, DE_2000_ = +66 23 46, z=0.1737) does
RXJ1747.9+6623 not show any emission line in the spectrum and resembles an
RXJ1747.9+6623 edge-on spiral in our UH 2.2m open image.
RXJ1748.5+7005Identification and redshift for this BL Lac comes from the
RXJ1748.5+7005 literature. An optical spectrum is published in Figure 7 of
RXJ1748.5+7005 Lawrence et al. (1996ApJS..107..541L); see also note in
RXJ1748.5+7005 Rector & Stocke (2001AJ....122..565R).
RXJ1748.6+6842There are two AGNs with similar redshift (z=0.0537 and z=0.0540)
RXJ1748.6+6842 that are blended in the APM finder. The western object
RXJ1748.6+6842 (RA_2000_ = 17 48 38.3, DE_2000_ = +68 42 17) has broad
RXJ1748.6+6842 emission lines in its optical spectrum. We indicate this object
RXJ1748.6+6842 as the identification (AGN1). The eastern object
RXJ1748.6+6842 (RA_2000_ = 17 48 38.7, DE_2000_ = +68 42 16) has H{alpha} in
RXJ1748.6+6842 emission but it is difficult to assess the width of the
RXJ1748.6+6842 emission line since the spectrum is rather noisy. Both objects
RXJ1748.6+6842 look like spiral galaxies in our UH 2.2m open image. The two
RXJ1748.6+6842 objects might be interacting, and both could contribute to the
RXJ1748.6+6842 X-ray emission.
RXJ1751.2+6533This source is associated with the group of galaxies published
RXJ1751.2+6533 in Figure 1e of Henry et al. (1995ApJ...449..422H). The
RXJ1751.2+6533 redshift has been updated using more accurate low-redshift data
RXJ1751.2+6533 from Falco et al. (1999PASP..111..438F).
RXJ1751.5+7013This source is identified with a cluster of galaxies at
RXJ1751.5+7013 z=0.4925. The two galaxies, for which we have optical spectra,
RXJ1751.5+7013 have narrow emission lines typical of AGN2. One of the AGN2
RXJ1751.5+7013 (RA_2000_ = 17 52 33.1, DE_2000_ = +70 13 01, z=0.4936) has a
RXJ1751.5+7013 narrow Mg II line in emission, in addition to H{beta} and to
RXJ1751.5+7013 [O II] and [O III] lines.
RXJ1752.2+6522This source is identified as a cluster of galaxies at z=0.3923.
RXJ1752.2+6522 There is also an emission-line object
RXJ1752.2+6522 (RA_2000_ = 17 52 12.9, DE_2000_ = +65 22 36) that is 15.1"
RXJ1752.2+6522 away from the X-ray position with z=0.3940. We still identify
RXJ1752.2+6522 the source with a cluster of galaxies since the spectrum of the
RXJ1752.2+6522 AGN, with H{beta} in emission, is too noisy to assess the width
RXJ1752.2+6522 of the line.
RXJ1753.9+7016This source is MS 1754.5+7017 and is identified as an AGN1 at
RXJ1753.9+7016 z=0.062 by Stocke et al. (1991ApJS...76..813S).
RXJ1754.0+6452The redshift for this cluster is tentative because it is based
RXJ1754.0+6452 on three low S/N spectra.
RXJ1754.6+6803This is MS 1754.9+6803. The redshift (z=0.0770) was measured by
RXJ1754.6+6803 Stocke et al. (1991ApJS...76..813S) and is based on three
RXJ1754.6+6803 galaxy spectra taken at the MMT in 1985 April.
RXJ1756.2+7042This is one of the two still unidentified sources in the whole
RXJ1756.2+7042 NEP survey. The X-ray source is a double source elongated in
RXJ1756.2+7042 the east-west direction. The eastern X-ray centroid is
RXJ1756.2+7042 identified with an AGN1 (RA_2000_ = 17 56 14.9,
RXJ1756.2+7042 DE_2000_ = +70 41 56, z=0.838) since it shows a broad Mg II
RXJ1756.2+7042 line in emission in its optical spectrum. The western source is
RXJ1756.2+7042 still unidentified. We have taken spectra for several objects
RXJ1756.2+7042 in the area using the Keck II, but none of the objects seems to
RXJ1756.2+7042 be a satisfactory identification.
RXJ1757.2+7033This source is MS 1757.7+7034, identified by Stocke et al.
RXJ1757.2+7033 (1991ApJS...76..813S) as a BL Lac at z=0.407, from Ca II H and
RXJ1757.2+7033 K, G band, and Mg I b absorption lines.
RXJ1757.2+6547This X-ray source, identified with an M star
RXJ1757.2+6547 (RA_2000_ = 17 57 14.3, DE_2000_ = +65 46 58, m_E_=14.68), is
RXJ1757.2+6547 9.4" away from the X-ray centroid in the APM finders. There is
RXJ1757.2+6547 also an AGN1 (RA_2000_ = 17 57 13.6, DE_2000_ = +65 46 45,
RXJ1757.2+6547 z=0.578) 15.7" away from the X-ray centroid with m_E_=19.53 and
RXJ1757.2+6547 m_O_=20.0. The AGN1 could also contribute to the X-ray emission
RXJ1757.2+6547 of the source.
RXJ1757.3+6631There are five spectroscopic redshifts for this cluster at
RXJ1757.3+6631 z=0.6909. The spectra were taken at the CFHT. None of the five
RXJ1757.3+6631 galaxies are visible on the APM, thus the optical positions are
RXJ1757.3+6631 approximate coordinates measured from the DSS-2 red plate. Two
RXJ1757.3+6631 of the cluster galaxies (cfh 2 at RA_2000_ = 17 57 46.3,
RXJ1757.3+6631 DE_2000_ = +66 30 26, z=0.7006; and cfh 8 at
RXJ1757.3+6631 RA_2000_ = 17 57 29.9, DE_2000_ = +66 32 29, z=0.6860) are
RXJ1757.3+6631 identified as AGN2 galaxies since their optical spectra show
RXJ1757.3+6631 similar narrow forbidden [O III], [O II] and permitted H{beta}
RXJ1757.3+6631 and H{gamma} emission lines.
RXJ1757.9+6609This source is identified with an AGN2 (RA_2000_ = 17 57 56.5,
RXJ1757.9+6609 DE_2000_ = +66 09 20, z=0.4865) only 4" away from the X-ray
RXJ1757.9+6609 position. See Figure 6 for an optical spectrum of the AGN2.
RXJ1757.9+6609 However, spectroscopic redshifts for two galaxies
RXJ1757.9+6609 (RA_2000_ = 17 58 02.1, DE_2000_ = +66 09 34, and
RXJ1757.9+6609 RA_2000_ = 17 58 00.6, DE_2000_ = +66 07 35) that are located
RXJ1757.9+6609 36" and 106" away from the X-ray centroid, respectively, are
RXJ1757.9+6609 concordant with the redshift of NEP super cluster (z=0.089)
RXJ1757.9+6609 found in the NEP survey by Mullis et al. (2001, Ph.D. thesis,
RXJ1757.9+6609 Inst. for Astronomy, Univ. Hawaii).
RXJ1758.9+6520This source is identified with a cluster of galaxies at
RXJ1758.9+6520 z=0.3652. Three cluster galaxies spectroscopically observed
RXJ1758.9+6520 have narrow emission lines (see Fig. 7 for an example of one
RXJ1758.9+6520 cluster member, namely, galaxy C at RA_2000_ = 17 58 53.8,
RXJ1758.9+6520 DE_2000_ = +65 21 02, z_C_=0.3665). A fourth object in the
RXJ1758.9+6520 field at RA_2000_ = 17 59 02.8, DE_2000_ = +65 20 55, has broad
RXJ1758.9+6520 emission lines and is thus identified as AGN1 (z=0.3660). The
RXJ1758.9+6520 identification of the source is still a cluster of galaxies
RXJ1758.9+6520 based on the distance of the AGN1 from the X-ray position
RXJ1758.9+6520 (~35"), but a contribution to the X-ray emission from the AGN1
RXJ1758.9+6520 is not excluded. Thus, this source is a case of cluster
RXJ1758.9+6520 plus AGN.
RXJ1759.7+6629This X-ray source (AGN1 at z=0.399) was already identified by
RXJ1759.7+6629 Bower et al. (1996MNRAS.281...59B). We took an additional
RXJ1759.7+6629 spectrum to confirm the QSO nature.
RXJ1800.0+6645This X-ray source is the same as RX J1800.0+6646 in Bower et al.
RXJ1800.0+6645 (1996MNRAS.281...59B) and was identified as a G type star. Our
RXJ1800.0+6645 spectrum confirms that the object is a G-K type star.
RXJ1800.1+6636This X-ray source was already identified by Bower et al.
RXJ1800.1+6636 (1996MNRAS.281...59B) as a Sy2 galaxy (NGC 6552). We took an
RXJ1800.1+6636 additional spectrum (z=0.0260) to confirm the AGN2 nature.
RXJ1801.2+6902The redshift for this source (AGN1, z=1.27) comes from Lacy et
RXJ1801.2+6902 al. (1993MNRAS.263..707L).
RXJ1801.2+6624This X-ray source was already identified in Bower et al.
RXJ1801.2+6624 (1996MNRAS.281...59B) as a QSO at z=1.25.
RXJ1801.7+6638This is a bright X-ray source identified as a BL Lac in Bower et
RXJ1801.7+6638 al. (1996MNRAS.281...59B; see finding chart in their Fig. 2c
RXJ1801.7+6638 and an optical spectrum in their Fig. 6). The redshift is
RXJ1801.7+6638 unknown since the optical spectrum is featureless. A radio
RXJ1801.7+6638 source (1.07+/-0.04mJy at 6cm) was detected with the VLA in the
RXJ1801.7+6638 DnC array at the position of the optical source by T. Rector
RXJ1801.7+6638 (2003, private communication).
RXJ1802.0+6629This source was identified as a BL Lac in Bower et al.
RXJ1802.0+6629 (1996MNRAS.281...59B) given the very weak or almost absent
RXJ1802.0+6629 lines in the spectrum they obtained at the Multiple Mirror
RXJ1802.0+6629 Telescope (see their Fig. 3). An optical spectrum of this same
RXJ1802.0+6629 source was obtained by us in 1999 July with KeckII-LRIS (see
RXJ1802.0+6629 Fig. 12). Strong and broad Balmer emission lines are visible in
RXJ1802.0+6629 our spectrum consistent with an AGN1 object, possibly a
RXJ1802.0+6629 variable QSO?
RXJ1802.7+6727This source is identified as an AGN2 at z=0.1620. There are two
RXJ1802.7+6727 possibly interacting spiral galaxies with optical narrow
RXJ1802.7+6727 emission lines in their spectra, which are blended on the APM
RXJ1802.7+6727 finder. The optical position of galaxy A1, at (z=0.1605), is
RXJ1802.7+6727 RA_2000_ = 18 02 47.8, DE_2000_ = +67 27 41, while the optical
RXJ1802.7+6727 position of galaxy A2, at z=0.1635, is RA_2000_ = 18 02 47.6,
RXJ1802.7+6727 DE_2000_ = +67 27 34. Both galaxies could be responsible for
RXJ1802.7+6727 part of the X-ray emission.
RXJ1803.4+6738This very bright NEP source is MS 1803+6728 and is identified as
RXJ1803.4+6738 AGN1. The redshift (z=0.1360) was measured by Stocke et al.
RXJ1803.4+6738 (1991ApJS...76..813S). The object is also listed in the QSO
RXJ1803.4+6738 catalog by Hewitt & Burbidge (Cat. VII/158) as HB89, and
RXJ1803.4+6738 in the X-ray NORAS catalog by Boehringer et al.
RXJ1803.4+6738 (2000ApJS..129..435B) as a tentative AGN. Optical spectra taken
RXJ1803.4+6738 at Lick and Multiple Mirror Telescope observatories are shown
RXJ1803.4+6738 in Figure 4 of Treves et al. (1995ApJ...442..589T).
RXJ1803.9+6548The redshift for this BL Lac (z=0.0850) is tentative since it
RXJ1803.9+6548 has been derived from very weak absorption lines. The source is
RXJ1803.9+6548 also identified with the VLA radio source NEP J1803.9+6548 by
RXJ1803.9+6548 Kollgaard et al. (1994ApJS...93..145K), and it is in the
RXJ1803.9+6548 radio-loud ROSAT NEP sources detected with the VLA at 1.5GHz
RXJ1803.9+6548 by Brinkmann et al. (1999A&AS..134..221B) with a
RXJ1803.9+6548 flux =43.1+/-1.7mJy (see more references therein).
RXJ1804.3+6629This source is identified with a very hot, subdwarf star. Its
RXJ1804.3+6629 optical position, RA_2000_ = 18 04 24.7, DE_2000_ = +66 29 28,
RXJ1804.3+6629 is 26" away from the X-ray position. There is a second object
RXJ1804.3+6629 in the field that is closer (RA_2000_ = 18 04 20.6,
RXJ1804.3+6629 DE_2000_ = +66 29 54) to the center of the X-ray emission and
RXJ1804.3+6629 for which no spectrum is available. However, this second object
RXJ1804.3+6629 is quite faint, is not blue on the DSS, does not have any
RXJ1804.3+6629 radio emission, and thus is unlikely to be an AGN.
RXJ1806.1+6813This source is identified as cluster of galaxies at z=0.303.
RXJ1806.1+6813 Four out of six galaxies for which we have taken spectra are
RXJ1806.1+6813 emission-line galaxies, all with concordant redshifts. One of
RXJ1806.1+6813 the four galaxies (RA_2000_ = 18 06 04.8, DE_2000_ = +68 13 08,
RXJ1806.1+6813 z=0.2953) has broad Balmer (FWHM=2500km/s). Thus, this source
RXJ1806.1+6813 is a case of cluster plus AGN.
RXJ1806.4+7028This source is identified as a galaxy and has an X-ray
RXJ1806.4+7028 luminosity L_X_=1.8x10^43^erg/s (assuming kT=2keV), which is
RXJ1806.4+7028 high for a galaxy with no emission lines. As first noted by
RXJ1806.4+7028 Mullis (2001, Ph.D. thesis, Inst. for Astronomy, Univ. Hawaii)
RXJ1806.4+7028 it could be an example of overluminous galaxies found in X-ray
RXJ1806.4+7028 surveys (e.g., Vikhlinin et al. 1999ApJ...520L...1V and
RXJ1806.4+7028 references therein).
RXJ1806.8+6949This is a BL Lac in a cluster of galaxies. Redshift comes from
RXJ1806.8+6949 Falco et al. (1999PASP..111..438F).
RXJ1808.8+6634The redshift for this source, identified as AGN1 at z=0.697,
RXJ1808.8+6634 comes from Laurent-Muehleisen et al. (1998ApJS..118..127L).
RXJ1808.8+6634 See their Table 2 for source properties.
RXJ1810.3+6328This source, identified as AGN1 at z=0.838, has a double
RXJ1810.3+6328 morphology in X-rays. The identification of the X-ray source
RXJ1810.3+6328 given in Table 3 refers to the western lobe
RXJ1810.3+6328 (RA_2000_ = 18 10 31.1, DE_2000_ = +63 28 08, z=0.838). The
RXJ1810.3+6328 eastern lobe is an AGN1 at z=1.0907 (RA_2000_ = 18 10 16.9,
RXJ1810.3+6328 DE_2000_ = +63 29 14).
RXJ1815.4+6806The redshift for this QSO (z=0.239) comes from Lacy et al.
RXJ1815.4+6806 (1993MNRAS.263..707L).
RXJ1821.9+6420The identification of this source as a QSO at z=0.2970 comes
RXJ1821.9+6420 from Pravdo & Marshall (1984ApJ...281..570P; see an optical
RXJ1821.9+6420 spectrum in their Fig. 2). However, as already noted by
RXJ1821.9+6420 Hutchings & Neff (1991AJ....101.2001H, see their Fig. 1), a
RXJ1821.9+6420 cluster of galaxies for which six galaxy spectra were taken by
RXJ1821.9+6420 Schneider et al. (1992AJ....103.1047S) is present at the same
RXJ1821.9+6420 redshift as the QSO (see detailed description of this
RXJ1821.9+6420 QSO/cluster source in Wold et al., 2002MNRAS.335.1017W and
RXJ1821.9+6420 references therein). The X-ray source has the highest S/N of
RXJ1821.9+6420 the whole NEP survey, it is extremely X-ray luminous
RXJ1821.9+6420 (L_X_=5.61x10^45^erg/s), and it is also an IRAS source, as
RXJ1821.9+6420 reported by de Grijp et al. (1992A&AS...96..389D).
RXJ1826.6+6706This source is identified with an AGN1 at z=0.287. The redshift
RXJ1826.6+6706 comes from Lacy et al. (1993MNRAS.263..707L).
RXJ1832.5+6848This source is identified as a cluster of galaxies at z=0.205.
RXJ1832.5+6848 We took optical spectra for three galaxies and they have
RXJ1832.5+6848 concordant redshifts. The source is listed in the literature as
RXJ1832.5+6848 the radio source 7C 1832+6845, and it is identified as QSO by
RXJ1832.5+6848 Veron-Cetty & Veron (2001A&A...374...92V), and as BL Lac in the
RXJ1832.5+6848 NORAS catalog by Boehringer et al. (2000ApJS..129..435B). The
RXJ1832.5+6848 ambiguity may be due to the fact that there are two distinct
RXJ1832.5+6848 objects very closely separated (~6") at the position of the
RXJ1832.5+6848 X-ray source. The northwest object, object A, is the object we
RXJ1832.5+6848 have observed spectroscopically (RA_2000_ = 18 32 35.6,
RXJ1832.5+6848 DE_2000_ = +68 48 09, z=0.2049). It is red on the DSS, and its
RXJ1832.5+6848 spectrum shows narrow Balmer and oxygen emission lines,
RXJ1832.5+6848 consistent with an AGN2 object (unless we caught the QSO in a
RXJ1832.5+6848 quiescent state). The southeast object A1
RXJ1832.5+6848 (RA_2000_ = 18 32 36.2, DE_2000_ = +68 48 04) appears blue on
RXJ1832.5+6848 the DSS and could be the object indicated as QSO or BL Lac in
RXJ1832.5+6848 the literature. No spectrum is available for A1. A second
RXJ1832.5+6848 galaxy in the cluster (object B at RA_2000_ = 18 32 35.9,
RXJ1832.5+6848 DE_2000_ = +68 47 43, z=0.2048) also shows narrow emission
RXJ1832.5+6848 lines and it is classified as AGN2 in the cluster. The third
RXJ1832.5+6848 galaxy for which we obtained a spectrum, object C
RXJ1832.5+6848 (RA_2000_ = 18 32 35.6, DE_2000_ = +68 47 58, z=0.2054), shows
RXJ1832.5+6848 no emission lines in its spectrum.
RXJ1834.1+7057This source is very extended in X-rays, and it is identified
RXJ1834.1+7057 with a cluster of galaxies at z=0.0803. An extraction radius of
RXJ1834.1+7057 6.5' has been used, different from the normal 5' radius used
RXJ1834.1+7057 for the rest of the X-ray sources. The X-ray position is
RXJ1834.1+7057 centered on a bright galaxy (RA_2000_ = 18 34 08.5,
RXJ1834.1+7057 DE_2000_ = +70 57 19, m_E_=~12.5), possibly the cD, whose
RXJ1834.1+7057 redshift appears in the NORAS catalog of Boehringer et al.
RXJ1834.1+7057 (2000ApJS..129..435B) as z=0.0824. The source is in the same
RXJ1834.1+7057 region of sky as A2308, even if the Abell cluster position in
RXJ1834.1+7057 the NED database is at RA_2000_ = 18 33 33.8 and
RXJ1834.1+7057 DE_2000_ = +71 01 28. The redshift given in Table 3 has been
RXJ1834.1+7057 computed using spectra for three galaxies taken by us at the
RXJ1834.1+7057 UH 2.2m. The redshift agrees with other redshift determinations
RXJ1834.1+7057 listed in NED for A2308.
RXJ1842.5+6809Redshift for this AGN1, z=0.4750, comes from the literature. The
RXJ1842.5+6809 QSO is listed in the catalog by Hewitt & Burbidge (Cat. VII/158
RXJ1842.5+6809 1993ApJS...87..451H ) and in Xu et al. (1994AJ....108..395X).