Sasmirala Individual Information for MR 2251-178
Description
MR 2251-178 is a quasar-regime AGN at a redshift of z = 0.0640 (D ~ 271 Mpc) with an optical Sy 1.5 classification [veron-cetty_catalogue_2010]. It was the first quasar discovered in X-rays and the second quasar with X-ray detection after 3C 273 [ricker_discovery_1978]. Since then it has been extensively studied in X-rays and also belongs to the nine-month BAT AGN sample. Initial MIR observations were performed by [soifer_infrared_1979], followed by [elvis_atlas_1994]. MR 2251-178 appears point-like in the Spitzer/IRAC and MIPS images. In the IRS LR mapping-mode spectrum, significant silicate 10 μm emission can be identified, while the continuum has a flat spectral slope in νFν-space. We observed MR 2251-178 with VISIR in three narrow N-band filters in 2009. The weakly detected MIR nucleus appears extended and elongated in all images, in particular the SIV_2 filter, but with inconsistent position angles between 40 and 90∘. Therefore, it remains uncertain whether MR 2251-178 is truly extended in the MIR at subarcsecond resolution, and at least another epoch of deeper MIR imaging is needed. The VISIR photometry agrees with the Spitzer spectrophotometry and indicates the same strong silicate 10 μm emission feature, which is also consistent with the previous MIR photometry described above.
- [elvis_atlas_1994] Martin Elvis, Belinda J. Wilkes, Jonathan C. McDowell, Richard F. Green, Jill Bechtold, S. P. Willner, M. S. Oey, Elisha Polomski, and Roc Cutri. Atlas of quasar energy distributions . ApJS , 95 pp. 1–68, November 1994.
- [ricker_discovery_1978] G. R. Ricker, G. W. Clark, R. E. Doxsey, R. G. Dower, J. G. Jernigan, J. P. Delvaille, G. M. MacAlpine, and R. M. Hjellming. Discovery of an x-ray QSO . Nature , 271 pp. 35–37, January 1978.
- [soifer_infrared_1979] B. T. Soifer, G. Neugebauer, and K. Matthews. Infrared observations of the x-ray quasars 0241+622 and MR2251-178 . Nature , 278 pp. 231, March 1979.
- [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.