NASA/IPAC EXTRAGALACTIC DATABASE
Date and Time of the Query: 2019-04-21 T11:45:46 PDT
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Notes for object MRK 0684

4 note(s) found in NED.


1. 2006A&A...457...61R
Re:Mrk 0684
Mrk 684. Osterbrock & Pogge (1985) classified this object as a NLS1.
Indeed, optical spectroscopy reveals prominent Fe II emission and broad
Balmer lines with FHWM of only 1300 km s^-1^ (Persson 1988). The NIR
spectrum is dominated by permitted lines of H I and He I with FWHM
approx 1150 km s^-1^. Permitted lines of Fe II, O I and Ca II (seen in
emission) are also detected but with slightly narrower FWHM (900 km
s^-1^), suggesting that they are formed in the outer portions of the
BLR. The NLR emission is almost absent, while [S III] 9531 Angstrom is
likely to be present but is strongly blended with Pa 8 to make a secure
detection. The continuum emission is rather steep and featureless. No
evidence of stellar absorption features was found. Like PG1415+451, it
has the appearance of a naked type I source.

2. 2001A&A...372..730V
Re:MRK 0684
Mark 684 (1428+28) is an NLS1 (Osterbrock & Pogge 1987) with prominent
Fe II emission (Persson 1988).
On the red spectrum, the broad line component is poorly fitted by a
single Lorentzian; a second, Gaussian component is needed. The broad
H{beta} line is too weak for a meaningful fit to be made. The spectrum is
composite in the sense that the narrow line region has two components, one
with relatively broad lines, the other with very narrow lines and line
ratios typical of a H II region.

3. 2001A&A...368..797P
Re:MRK 0684
Mkn 684: For Mkn 684 we assume the classification as a NLS1 galaxy by
Osterbrock & Pogge (1985) and Grupe (1996).

4. 1995AJ....109...81U
Re:MRK 0684
Mrk 684. This galaxy has a 6 cm upper limit of 0.25 mJy at 6 cm. The
optical position has an accuracy of only 5" (Kojoian et al. 1978). In a 4
arcmin field centered on the position listed in Table 1, the only source
detected was a 1.7 mJy source located at (14^h^28^m^50.08^s^,
+28^deg^31'24.0"), more than an arcminute from the nominal position.
Unless the errors on the optical position were greatly underestimated,
this source is unrelated to the nucleus of Mrk 684. The optical
polarization of the galaxy is less than 0.2%.


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