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Date and Time of the Query: 2019-02-16 T19:18:39 PST
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Notes for object SN 1999bx

1 note(s) found in NED.


1. 2003PASP..115....1V
Re:SN 1999bx
3.4. SN 1999bx in NGC 6745
SN 1999bx was discovered using KAIT by Friedman & Li (1999). The
host galaxy, NGC 6745 (UGC 11391), may actually be an interacting galaxy
pair, and the SN occurred about 2" west and 15" north of the southern of
the two nuclei. Jha et al. (1999c) classified it as an SN II. From a
KAIT image, we measure the SN position as {alpha} = 19h01m41.39,
{delta} = +40deg44'52.0, with uncertainty +/-0.2". NGC 6745 was imaged
very deeply in F336W (22,000 s), F555W (4800 s), F675W (5200 s), and
F814W (5200 s) on 1997 March 19 and 21 by GO-6276. Applying the 2MASS
astrometric grid directly to the F555W mosaic, with total positional
uncertainty +/-0.4", we show in Figure 5 the SN site on the WF3 chip.
We detect four objects (AD) within, or along the edge of, the
error circle, and with the good color coverage discussed above, we can
derive useful information about them. HSTphot considers the two objects
at the western circle edge, A and B, to be stellar, with
V = 24.37 +/- 0.09 and 25.01 +/- 0.20 mag, respectively, whereas the two
eastern objects, C and D, are likely extended, with V = 23.75 +/- 0.01
and 23.53 +/- 0.01 mag, respectively. Assuming a distance of about 74 Mpc
and Galactic extinction A_V_ = 0.44 mag, the two western objects, A and B,
have M_V_ = -10.4 and -9.8 mag, respectively, certainly at the upper
end of possible stellar luminosities, while the two eastern objects,
C and D, have M_V_ = -11.0 and -11.3 mag, respectively, almost certainly
too bright to be single stars. Additionally, objects A and B are quite
blue: for A, the reddening-corrected colors are (U-V)^0^ = -0.38,
(V-R)^0^ = 0.01, (R-I)^0^ = 0.19, and (V-I)^0^ = 0.20 mag; and, for
object B, (U-V)^0^ = -0.56, (V-R)^0^ = 0.60, (R-I)^0^ = 0.20, and
(V-I)^0^ = 0.80 mag. Colors for object B indicate that it may be a
composite of blue and red objects.
It is therefore likely that the detected objects are too luminous
and too blue to be the possible progenitor of SN 1999bx, since as an
SN II, we might expect the progenitor to have been a red supergiant.
We cannot rule out that the progenitor was either an unresolved member
of likely clusters C and D, or was blended with luminous stellar objects
A or B. However, if it is undetected, limits on the absolute magnitude
and color of the progenitor are M_V_^0^ >~ -7.8, (U-V)^0^ <~ 0.5,
(V-R)^0^ <~ 0.9, (R-I)^0^ <~ 1.0, and (V-I)^0^ <~ 1.6 mag. (Color limits
here and throughout are derived from the larger SN environment, ~10"
or so, depending on the image, and are not particularly restrictive.)


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