Description
Mrk 304 is an ultra-luminous infrared, extremely compact galaxy at a redshift of z = 0.066 (D ~ 301 Mpc),
hosting a radio-quiet borderline quasar with Sy 1 classification [veron-cetty_catalogue_2010]. No
subarcsecond-resolution radio observations are reported in the literature, only a low-resolution point source was
detected [kellermann_radio_1994]. Pioneering MIR observations were performed by [rieke_infrared_1978],
followed by Spitzer/IRS and MIPS and appears as a compact source in the corresponding MIPS 24 μm image. The
IRS LR staring-mode spectrum exhibits prominent silicate 10 and 18 μm emission and a blue spectral slope in
νFν-space but no PAH features (see also [schweitzer_spitzer_2006, schweitzer_extended_2008,
shi_aromatic_2007]). Mrk 304 was imaged with COMICS in the N11.7 filter in 2006 [imanishi_subaru_2011], and
a compact nucleus without further host emission was detected. The nucleus appears to be marginally resolved
(FWHM~ 0.56arcsec ~ 0.7 kpc) but at least another epoch of subarcsecond MIR imaging is required to verify this
extension. Our nuclear N11.7 photometry is ~ 25% higher than the value by [imanishi_subaru_2011] for unknown
reasons, and also higher than but still consistent with the Spitzer spectrophotometry. Therefore, we use the latter to
compute the nuclear 12 μm continuum emission estimate corrected for the silicate feature. Note however, that the
nuclear flux would be significantly lower if the presence of subarcsecond-extended emission can be verified. For now,
the resulting synthetic flux is scaled by half of the ratio between FνPSF and FνGau to account for the possibly
nuclear extension.
-
[imanishi_subaru_2011] Masatoshi Imanishi,
Keisuke Imase, Nagisa Oi, and Kohei Ichikawa.
Subaru and
gemini high spatial resolution infrared 18 μm imaging observations of nearby
luminous infrared galaxies
.
AJ
,
141
pp. 156, May 2011.
-
[kellermann_radio_1994] K. I. Kellermann, R. A.
Sramek, M. Schmidt, R. F. Green, and D. B. Shaffer.
The radio
structure of radio loud and radio quiet quasars in the palomar bright quasar
survey
.
AJ
,
108
pp. 1163–1177, October 1994.
-
[rieke_infrared_1978] G. H. Rieke.
The infrared
emission of seyfert galaxies
.
ApJ
,
226
pp. 550–558, December 1978.
-
[schweitzer_extended_2008] M. Schweitzer,
B. Groves, H. Netzer, D. Lutz, E. Sturm, A. Contursi, R. Genzel, L. J.
Tacconi, S. Veilleux, D.-C. Kim, D. Rupke, and A. J. Baker.
Extended
silicate dust emission in palomar-green QSOs
.
ApJ
,
679
pp. 101–117, May 2008.
-
[schweitzer_spitzer_2006] M. Schweitzer,
D. Lutz, E. Sturm, A. Contursi, L. J. Tacconi, M. D. Lehnert, K. M. Dasyra,
R. Genzel, S. Veilleux, D. Rupke, D.-C. Kim, A. J. Baker, H. Netzer,
A. Sternberg, J. Mazzarella, and S. Lord.
Spitzer quasar
and ULIRG evolution study (QUEST). i. the origin of the far-infrared
continuum of QSOs
.
ApJ
,
649
pp. 79–90, September 2006.
-
[shi_aromatic_2007] Yong Shi, Patrick Ogle,
George H. Rieke, Robert Antonucci, Dean C. Hines, Paul S. Smith, Frank J.
Low, Jeroen Bouwman, and Christopher Willmer.
Aromatic
features in AGNs: star-forming infrared luminosity function of AGN host
galaxies
.
ApJ
,
669
pp. 841–861, November 2007.
-
[veron-cetty_catalogue_2010] M.-P.
Véron-Cetty and P. Véron.
A catalogue
of quasars and active nuclei: 13th edition
.
A&A
,
518
pp. 10, July 2010.
Images
Optical image (DSS, red filter). Displayed are the
central 4 arcmin with North being up and East to the left. The colour
scaling is linear with white corresponding to the median background (BG)
and black to the 0.01% pixels with the highest intensity.
Spitzer MIR images. Displayed are the inner 40 arcsec
with North being up and East to the left. The colour scaling is logarithmic
with white corresponding to median BG and black to the 0.1% pixels with the
highest intensity. The label in the bottom left states instrument and
central wavelength of the filter in micron (I: IRAC, M: MIPS).
Subarcsecond-resolution MIR images sorted by increasing
filter central wavelength. Displayed are the inner 4 arcsec with North
being up and East to the left. The colour scaling is logarithmic with white
corresponding to median BG and black to the 75% of the highest intensity of
all images in units of sig_bg. The inset image (where present; either
bottom or top right) shows the central arcsecond of the PSF from the
calibrator star, scaled to match the science target. The labels in the
bottom left state instrument and filter names (C: COMICS, M: Michelle, T:
T-ReCS, V: VISIR).
SEDs
MIR SED. The description of the symbols in all the SED plots (where
present) is the following: Grey crosses and solid lines mark the
Spitzer/IRAC, MIPS and IRS data. The colour coding of the other symbols is
as follows: green for COMICS, magenta for Michelle, blue for T-ReCS and red
for VISIR data. Darker-coloured solid lines mark spectra of the
corresponding instrument. The black filled circles mark the nuclear 12 and
18 micron continuum emission estimate from the data (where present). The
ticks on the top axis mark positions of common MIR emission lines, while
the light grey horizontal bars mark wavelength ranges affected by the
silicate 10 and 18 micron features.