Sasmirala Individual Information for NGC 7552

Description

NGC 7552 is an infrared-luminous, nearly face-on, barred spiral galaxy at a redshift of z = 0.0054 (D ~ 20.4 Mpc) with a possibe active nucleus surrounded by a powerful circum-nuclear starburst ring (diameter~ 5arcsec ~ 0.5 kpc; [forbes_nuclear_1994, forbes_ngc_1994]; see [pan_formation_2013, brandl_high_2012] for recent detailed studies). The nucleus has been optically classified as a LINER [durret_imaging_1987] or H II [yuan_role_2010]. The presence of an AGN is supported by the detection of a compact nuclear source in hard X-rays [grier_discovery_2011, brightman_xmm-newton_2011]. However, we conservatively treat NGC 7552 as an uncertain AGN. Initial MIR observations of NGC 7552 are reported in [kleinmann_10-micron_1974], followed by many ground-based observations [frogel_8-13_1982, phillips_8-13_1984, roche_atlas_1991, schinnerer_circumnuclear_1997, siebenmorgen_mid-infrared_2004]. The latter two works present the first subarcsecond-resolution MIR images, which resolve the starburst ring as a clumpy structure. NGC 7552 was also observed with the space-based ISO [rigopoulou_large_1999, roussel_atlas_2001, verma_mid-infrared_2003] and Spitzer/IRAC, IRS and MIPS. The corresponding IRAC and MIPS images do not completely resolve the starburst ring, which appears as a dominating central source embedded within the spiral-like host galaxy emission (see also [brandl_high_2012]). We measure the nuclear flux component in the non-saturated IRAC 5.8 μm and MIPS 24 μm post-BCD images, which conclusively results in significantly lower values than in the literature (e.g. [dale_infrared_2005, munoz-mateos_radial_2009]). The IRS LR mapping-mode spectrum shows strong PAH emission and possibly weak silicate 10 μm absorption with a red spectral slope in νFν-space (see also [smith_mid-infrared_2007, marble_aromatic_2010]). As expected, the arcsecond-scale MIR SED appears to be star-formation dominated. The nuclear region of NGC 7552 was imaged with VISIR in eleven N-band and one Q-band filters in 2005 (partly published in [brandl_high_2012]). At least the brightest knots of the starburst ring are detected in all images, while the nucleus remains undetected (see [brandl_high_2012] for the analysis of the ring). A compact source is faintly visible at the nuclear position (< 2σ) only in the longest-wavelength N-band filters. Therefore, we determine flux upper limits on the nuclear emission, which are on average ~ 94% lower than the Spitzer spectrophotometry. We conclude that a very weak AGN might be present in NGC 7552 but star formation is dominating its MIR emission completely.

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).

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.

Photometry details and reduced FITS files

ObjectRA
[deg]
Dec
[deg]
FilterImageInfoλ_c
[um]
HWHM
[um]
InstrPix. size
[arcsec/pix]
T_exp
[s]
ModeChop Throw
[arcsec]
Chop Angle
[deg]
Rot
[deg]
Prog IdCal. StarCal. DateDate Obs.Factor
[mJy/ct]
Err. Factor
[mJy/ct]
Cal. Flux
[mJy]
Upper Lim. Gauss?F_Gauss
[mJy]
E(F_Gauss)
[mJy]
Upper Lim. PSF?F_PSF
[mJy]
E(F_PSF)
[mJy]
Cal. Maj.
[arcsec]
Cal. Min.
[arcsec]
Cal. PA.
[deg]
Maj. Ax
[arcsec]
Min. Ax
[arcsec]
Pos. Ang.
[deg]
NGC 7552349.045000-42.584722SIV_2[Details]10.770.19VISIR0.127350.0PARA10.00.00.0075.B-0182(A)HD2160322005-06-23T10:33:36Z2005-06-23T09:44:38Z0.354630.0062931594.6True37.9N/ATrue37.9N/A0.410.3942.0N/AN/AN/A
NGC 7552349.045000-42.584722ARIII[Details]8.990.14VISIR0.127180.0PARA10.00.00.0075.B-0182(A)HD2186702005-06-10T10:19:12Z2005-06-10T09:41:46Z0.062410.0010910520.5True30.8N/ATrue30.8N/A0.450.4145.0N/AN/AN/A
NGC 7552349.045000-42.584722NEII[Details]12.810.21VISIR0.127508.0PARA10.00.00.0075.B-0182(A)HD2160322005-06-23T10:40:48Z2005-06-23T08:32:38Z0.581170.0102724005.5True77.7N/ATrue77.7N/A0.430.4130.0N/AN/AN/A
NGC 7552349.045000-42.584722NEII_1[Details]12.270.18VISIR0.127690.0PARA10.00.00.0075.B-0182(A)HD2160322005-06-23T10:40:48Z2005-06-23T08:15:22Z0.539670.0067525149.9True43.9N/ATrue43.9N/A0.440.4264.0N/AN/AN/A
NGC 7552349.045000-42.584722NEII_2[Details]13.040.22VISIR0.1271035.0PARA10.00.00.0075.B-0182(A)HD2160322005-06-23T10:48:00Z2005-06-23T08:44:10Z0.573350.0115323184.7True49.1N/ATrue49.1N/A0.40.3921.0N/AN/AN/A
NGC 7552349.045000-42.584722PAH1[Details]8.590.42VISIR0.127173.0PARA10.00.00.0075.B-0182(A)HD2186702005-06-10T10:13:26Z2005-06-10T09:37:26Z0.188570.0021411414.2True35.0N/ATrue35.0N/A0.470.43148.0N/AN/AN/A
NGC 7552349.045000-42.584722PAH2[Details]11.250.59VISIR0.127538.0PARA14.00.00.0075.B-0727(A)HD2096882005-06-15T10:24:58Z2005-06-15T07:42:14Z0.15640.007549155.1True57.5N/ATrue57.5N/A0.660.5918.0N/AN/AN/A
NGC 7552349.045000-42.584722PAH2_2[Details]11.880.37VISIR0.127538.0PARA14.00.00.0075.B-0727(A)HD1961712005-06-15T06:38:53Z2005-06-15T07:55:12Z0.39970.0600213649.6True60.2N/ATrue60.2N/A0.560.47156.0N/AN/AN/A
NGC 7552349.045000-42.584722Q2[Details]18.720.88VISIR0.1273638.0PARA11.00.00.0076.B-0656(A)HD2186702005-10-09T00:14:24Z2005-10-09T00:37:26Z0.475060.017072701.6True103.3N/ATrue103.3N/A0.550.52120.0N/AN/AN/A
NGC 7552349.045000-42.584722SIC[Details]11.852.34VISIR0.127362.0PARA10.00.00.0075.B-0182(A)HD2186702005-06-10T10:24:58Z2005-06-10T09:51:50Z0.067640.002246803.1True45.1N/ATrue45.1N/A0.490.43152.0N/AN/AN/A
NGC 7552349.045000-42.584722SIV[Details]10.490.16VISIR0.127362.0PARA10.00.00.0075.B-0182(A)HD2186702005-06-10T10:24:58Z2005-06-10T09:47:31Z0.058930.001158249.9True45.4N/ATrue45.4N/A0.50.45143.0N/AN/AN/A
NGC 7552349.045000-42.584722SIV_1[Details]9.820.18VISIR0.1272870.0PARA10.00.00.0075.B-0182(A)HD2160322005-06-23T10:30:43Z2005-06-23T09:12:58Z0.642050.0081637130.8True29.8N/ATrue29.8N/A0.410.38156.0N/AN/AN/A