Surface photometry of elliptical galaxies has become, in the last decades, a powerful tool to study the structure and general properties of these objects (Kormendy & Djorgovski 1989). A large database on surface photometry, especially in V band, has been produced, and refined techniques of analysis have been employed. For example, the isophote shapes give valuable information about the intrinsic structure of elliptical galaxies, like triaxiality (Bertola 1981); color indices and gradients give information on stellar content and metallicity (Tamura et al. 2000). Brightness profiles have been widely used to construct quantitative parametrizations of early-type systems, as the well-known de Vaucouleurs r^1/4 law, and the more recent Sérsic's r^1/n law. It was found, in several works, that the latter law fits a larger variety of profile shapes (Saraiva et al. 1999).

However, this large quantitative and qualitative analysis is far less established in the infrared bands, a situation that will probably change with the availability of the 2MASS survey. One of the first works analyzing the behavior of infrared scale parameters ( $R_{\rm e}$ , $\mu_{\rm e}$ ) was made by Pahre et al. (1998) who, using a large sample of early-type galaxies observed in the optical and in the near-infrared K band, found a variation of the slope of the Fundamental Plane (FP) relation with the wavelength. Mobasher et al. (1999) found similar results observing early-type galaxies in the Coma cluster at K band. There are very few analyses of isophotal parameters in the infrared $JHK_{\rm s}$ broadbands. It is not well established whether the observed properties of isophotes in the optical region - e.g. twists, Fourier parameters and ellipticity - are connected to its near-IR counterparts. Furthermore, information on J-H and H-K colors and color gradients is available only for a small number of early-type galaxies, although near-infrared colors are crucial to understand the properties of the stellar population and its distribution in these systems.

In order to make more information available on the near-infrared photometric properties of early-type systems, we present in this work detailed infrared surface photometry ( $JHK_{\rm s}$ ) analysis for a sample of 12 bright early-type galaxies. For some of them, these are the first near-IR data available. This sample is selected from a larger list of galaxies containing gas and dust (Macchetto et al. 1996; Ferrari et al. 1999), making near-infrared surface photometry important, since it is less affected than the optical by the interstellar medium.

This paper is structured as follows: in Sect. 2, we present the observations and data reduction; in Sect. 3, we present the analysis of the data; in Sect. 4, we present the results of the analysis; in Sect. 5, we discuss the main results; finally Sect. 6 presents the general conclusions.

Table 1: Observed galaxies.
Galaxy $\alpha$ $\delta$ Morph. $v_{\rm r}$ (km s^-1) $B_{\rm T}^0$ $A_{\rm B}$ Dist. (Mpc)

IC 5105 21 24 22.4 -40 32 06 E5 $5407\pm13$ 12.42 0.15 80.61

NGC 596 01 32 52.1 -07 01 55 E0/S0 $1876\pm11$ 11.66 0.16 29.57

NGC 636 01 39 06.5 -07 30 46 E1 $1860\pm6$ 12.22 0.11 28.83

NGC 720 01 53 00.4 -13 44 18 E5 $1745\pm7$ 11.13 0.07 25.89

NGC 1400 03 39 31.0 -18 41 22 S0 $558\pm14$ 11.89 0.28 7.16

NGC 1453 03 46 27.2 -03 58 09 E0 $3886\pm6$ 12.26 0.45 60.23

NGC 1600 04 31 39.9 -05 05 10 E4 $4688\pm8$ 11.83 0.19 72.35

NGC 7192 22 06 50.3 -64 18 56 S0 $2904\pm15$ 12.23 0.15 41.87

NGC 7562 23 15 57.3 +06 41 16 E2 $3608\pm5$ 12.37 0.45 57.29

NGC 7619 23 20 14.4 +08 12 22 E3 $3762\pm5$ 11.93 0.35 60.05

NGC 7626 23 20 42.3 +08 13 02 E1 $3405\pm4$ 12.06 0.31 53.99

NGC 7796 23 58 59.7 -55 27 23 E1 $3290\pm24$ 12.39 0.04 72.35

Galaxy	$\alpha$	$\delta$	Morph.	$v_{\rm r}$ (km s^-1)	$B_{\rm T}^0$	$A_{\rm B}$	Dist. (Mpc)
IC 5105	21 24 22.4	-40 32 06	E5	$5407\pm13$	12.42	0.15	80.61
NGC 596	01 32 52.1	-07 01 55	E0/S0	$1876\pm11$	11.66	0.16	29.57
NGC 636	01 39 06.5	-07 30 46	E1	$1860\pm6$	12.22	0.11	28.83
NGC 720	01 53 00.4	-13 44 18	E5	$1745\pm7$	11.13	0.07	25.89
NGC 1400	03 39 31.0	-18 41 22	S0	$558\pm14$	11.89	0.28	7.16
NGC 1453	03 46 27.2	-03 58 09	E0	$3886\pm6$	12.26	0.45	60.23
NGC 1600	04 31 39.9	-05 05 10	E4	$4688\pm8$	11.83	0.19	72.35
NGC 7192	22 06 50.3	-64 18 56	S0	$2904\pm15$	12.23	0.15	41.87
NGC 7562	23 15 57.3	+06 41 16	E2	$3608\pm5$	12.37	0.45	57.29
NGC 7619	23 20 14.4	+08 12 22	E3	$3762\pm5$	11.93	0.35	60.05
NGC 7626	23 20 42.3	+08 13 02	E1	$3405\pm4$	12.06	0.31	53.99
NGC 7796	23 58 59.7	-55 27 23	E1	$3290\pm24$	12.39	0.04	72.35

1 Introduction