R. Fockenbrock

The Calar Alto Deep Imaging Survey:

We present K-band number counts for the faint galaxies in the Calar Alto Deep Imaging Survey (CADIS). We covered 4 CADIS fields, a total area of 0.2 deg^2, in the broad band filters B, R and K. We detect about 4000 galaxies in the K-band images, with a completeness limit of K = 19.75 mag, and derive the K-band galaxy number counts in the range of 14.25 18 mag. We also find that most of the K = 18 – 20 mag galaxies have a B - K color bluer than the prediction of a no-evolution model for an L⋆ Sbc galaxy, implying either significant evolution, even for massive galaxies, or the existence of an extra population of small galaxies.

K

We report preliminary results of a deep near-infrared search for methane-absorbing brown dwarfs; almost 5 yr after the discovery of Gl 229b, there are only a few confirmed examples of this type of object. New J-band, wide-field images, combined with preexisting R-band observations, allow efficient identification of candidates by their extreme (R-J) colors. Follow-up measurements with custom filters can then confirm objects with methane absorption. To date, we have surveyed a total of 11.4 deg2 to J approximately 20.5 and R approximately 25. Follow-up CH4 filter observations of promising candidates in one-fourth of these fields have turned up no methane-absorbing brown dwarfs. With 90% confidence, this implies that the space density of objects similar to Gl 229b is less than 0.012 pc-3. These calculations account for the vertical structure of the Galaxy, which can be important for sensitive measurements. Combining published theoretical atmospheric models with our observations sets an upper limit of alpha</=0.8 for the exponent of the initial mass function power law in this domain.

-band Galaxy number counts

The Calar Alto Deep Imaging Survey (CADIS) employs a combination of deep exposures in three broad bands (B,R,K) and up to 13 medium bands (R = λ/Δλ = 25... 50) with spectroscopic scans through an imaging Fabry-Perot-Interferometer (R ≃ 450). The survey will cover 10 fields of > 100□′, i.e. a total area of 0.3 □°. Although primarily designed to detect faint emission line galaxies at various intermediate (z = 0.2 ...1.4) and very high redshifts (z = 4.7, 5.7, 6.5) its multi-color strategy will also allow the detection and classification of hundreds of early type galaxies, faint QSOs, and extremely faint stars in our Galaxy. This contribution outlines the survey concept and its principal goals and then focuses on the expectations and first results of the search for “primeval” Ly-α emitting galaxies at z ≳ 5. More details about the data analysis and first results on faint field galaxies at intermediate redshift are presented in the contributions by Fockenbrock et al. and Thommes et al. to these proceedings.

Constraints on the Space Density of Methane Dwarfs and the Substellar Mass Function from a Deep Near-Infrared Survey.

The Calar Alto Deep Imaging Survey (CADIS) is a very deep emission line survey (using a Fabry-Perot (FP)) combined with deep broad- and medium-band photometry (for details see Meisenheimer et. al., these proceedings). Though this survey project is specifically designed to detect primeval galaxies it will in addition produce a large data base for investigations of faint galaxies at intermediate redshifts (0.2 < z < 1.2). In this contribution we present some first results concerning these forground objects which we got from the first data recorded with the CADIS strategy. These data were taken with the 2.2m telescope at Calar Alto in the CADIS field 9H. Due to delays in getting the 2k×2k CCDs, we employed an a 1k×1k CCD (field of view 8′×8′). We got four FP settings in the wavelength region 814nm to 818.5nm (resolution=1.8nm). Every setting consists of 7 individual exposures of 1500 s integration. We reached a 5σ detection limit of S lim (5σ) ≈ 5×10-20W/m2. To get an estimate of the continuum near the emissions lines detected in the FP, we did exposures with a filter λ/Δλ=812/17 nm (F lim (5σ) ≈ 5.8 × 10-21W/(m2nm)). The FP exposures were supplemented by broad band exposures with the filters BV (centered at 500 nm, 5σ limit ≈ 25. m 8), Rc (5σ limit ≈ 25. m 0) and I (5σ limit ≈ 23. m 1). Further narrow band exposures with the filters 466/9 (F lim (5σ) ≈ 10.7 × 10-21W/(m2nm)), 612/10 (F lim (5σ) ≈ 10.8 10-21W/(m2nm)) and 614/28 (F lim (5σ) ≈ 6.6 × 10-21W/(m2nm)) enable to detect further emission lines of foreground objects.

The Calar Alto Deep Imaging Survey for Primeval Galaxies

The Calar Alto Deep Imaging Survey (CADIS) is a very deep emission line survey using a Fabry-Perot (FP), combined with deep broad- and medium-band photometry (for an overview see Hippelein et al. 1996). This survey is specifically designed to detect primeval galaxies, but it will in addition produce a large data base for investigations of faint galaxies at intermediate redshifts (0.2 < z < 1.2). We present some first results from the initial data recorded with the CADIS strategy.