I. Apples to apples A2A^2: realistic galaxy simulated catalogs and photometric redshift predictions for next-generation surveys

We present new mock catalogues for two of the largest stage-IV next-generation surveys in the optical and infrared: LSST and Euclid, based on an N-body simulation+semi-analytical cone with a posterior modification with \texttt{PhotReal}. This technique modifies the original photometry by using an empirical library of spectral templates to make it more realistic. The reliability of the catalogues is confirmed by comparing the obtained color-magnitude relation, the luminosity and mass function and the angular correlation function with those of real data. Consistent comparisons between the expected photometric redshifts for different surveys are also provided. Very deep near infrared surveys such as Euclid will provide very good performance ($\Delta z/(1+z) \sim 0.025-0.053$) down to $H\sim24$ AB mag and up to $z\sim3$ depending on the optical observations available from the ground whereas extremely deep optical surveys such as LSST will obtain an overall lower photometric redshift resolution ($\Delta z/(1+z) \sim 0.045$) down to $i\sim27.5$ AB mag, being considerably improved ($\Delta z/(1+z) \sim 0.035$) if we restrict the sample down to i$\sim$24 AB mag. Those numbers can be substantially upgraded by selecting a subsample of galaxies with the best quality photometric redshifts. We finally discuss the impact that these surveys will have for the community in terms of photometric redshift legacy. This is the first of a series of papers where we set a framework for comparability between mock catalogues and observations with a particular focus on cluster surveys. The Euclid and LSST mocks are made publicly available in the following link: http://photmocks.obspm.fr/.Comment: accepted in MNRAS. Mocks available in the following link: http://photmocks.obspm.fr

The orthogonally aligned dark halo of an edge-on lensing galaxy in the Hubble Frontier Fields: a challenge for modified gravity

We examine a well-resolved lensed image that is bent by an edge-on lenticular galaxy, in the Hubble Frontier Fields (HFF) data of MACSJ0416.1−20403. The fortuitous combination of a long arc (zs ≈ 1 ± 0.2) intersecting an edge-on galaxy from the cluster (z = 0.4) provides an opportunity to constrain its dark matter (DM) halo and its orientation. We model the stellar lensing contribution and we add to this a standard parametrized dark halo component. Irrespective of the detailed choice of parameters, we obtain a combined total mass of ≈3 × 1011 M⊙. Depending on the dark halo parameters, the stellar contribution to this is limited to the range 5–15 × 1010 M⊙, or 20–50 per cent of the total mass, in good agreement with the independent (photmetric) stellar mass of 5 × 1010 M⊙ (Chabrier IMF), or 8 × 1010 M⊙ (Salpeter IMF). The major axis of the DM halo is constrained to be nearly orthogonal to the plane of the galaxy, and with an ellipticity e ≈ 0.15 corresponding to an axis ratio a/c = 0.54. We show that these conclusions are very weakly dependent on the model of the cluster, or the additional influence of neighbouring galaxies or the properties of the lensed source. Alternative theories of gravity that do not require DM are challenged by this finding since generically these must be tied to the baryonic component which is highly disfavoured by our results. Other such fortuitously useful lenses can be examined this way as they become uncovered with more HFF data to help provide a more statistical distribution of galaxy halo properties.JMD acknowledges support of the consolider project CAD2010-00064 and AYA2012-39475-C02-01 funded by the Ministerio de Economia y Competitividad.Peer Reviewe

Detection of Evolved High-Redshift Galaxies in Deep NICMOS/VLT Images

A substantial population of high redshift early-type galaxies is detected in very deep UBVRIJHK images towards the HDF-South. Four elliptical profile galaxies are identified in the redshift range z=1-2, all with very red SEDs, implying ages of >2 Gyrs for standard passive evolution. We also find later type IR-luminous galaxies at similarly high redshift, (10 objects with z>1, H1 Gyr. The number and luminosity-densities of these galaxies are comparable with the local E/SO-Sbc populations for \Omega_m>0.2, and in the absence of a significant cosmological constant, we infer that the major fraction of luminous Hubble-sequence galaxies have evolved little since z~2. A highly complete photometric redshift distribution is constructed to H=25 (69 galaxies) showing a broad spread of redshift, peaking at z~1.5, in reasonable agreement with some analyses of the HDF. Five `dropout' galaxies are detected at z~3.8, which are compact in the IR, ~0.5 kpc/h at rest 3500\AA. No example of a blue IR luminous elliptical is found, restricting the star-formation epoch of ellipticals to z>10 for a standard IMF and modest extinction.Comment: 7 pages, 3 figures, accepted for publication in Astrophysical Journal Letters, discussion of clustering added, color image available at http://astro.berkeley.edu/~tjb/nic3.htm

Photometric type Ia supernova surveys in narrow band filters

We study the characteristics of a narrow band type Ia supernova survey through simulations based on the upcoming Javalambre Physics of the accelerating universe Astrophysical Survey (J-PAS). This unique survey has the capabilities of obtaining distances, redshifts, and the SN type from a single experiment thereby circumventing the challenges faced by the resource-intensive spectroscopic follow-up observations. We analyse the flux measurements signal-to-noise ratio and bias, the supernova typing performance, the ability to recover light curve parameters given by the SALT2 model, the photometric redshift precision from type Ia supernova light curves and the effects of systematic errors on the data. We show that such a survey is not only feasible but may yield large type Ia supernova samples (up to 250 supernovae at $z<0.5$ per month of search) with low core collapse contamination ($\sim 1.5$ per cent), good precision on the SALT2 parameters (average $\sigma_{m_B}=0.063$, $\sigma_{x_1}=0.47$ and $\sigma_c=0.040$) and on the distance modulus (average $\sigma_{\mu}=0.16$, assuming an intrinsic scatter $\sigma_{\mathrm{int}}=0.14$), with identified systematic uncertainties $\sigma_{\mathrm{sys}}\lesssim 0.10 \sigma_{\mathrm{stat}}$. Moreover, the filters are narrow enough to detect most spectral features and obtain excellent photometric redshift precision of $\sigma_z=0.005$, apart from $\sim$ 2 per cent of outliers. We also present a few strategies for optimising the survey's outcome. Together with the detailed host galaxy information, narrow band surveys can be very valuable for the study of supernova rates, spectral feature relations, intrinsic colour variations and correlations between supernova and host galaxy properties, all of which are important information for supernova cosmological applications.Comment: 20 pages, 12 tables and 26 figures. Version accepted by MNRAS, with results slightly different from previous on

The magnification of SN 1997ff, the farthest known Supernova

With a redshift of z~1.7, SN 1997ff is the most distant type Ia supernova discovered so far. This SN is close to several bright, z=0.6-0.9 galaxies, and we consider the effects of lensing by those objects on the magnitude of SN 1997ff. We estimate their velocity dispersions using the Tully-Fisher and Faber-Jackson relations corrected for evolution effects,and calculate, applying the multiple-plane lensing formalism, that SN 1997ff is magnified by 0.34+-0.12 mag. Due to the spatial configuration of the foreground galaxies, the shear from individual lenses partially cancels out,and the total distortion induced on the host galaxy is considerable smaller than that produced by a single lens having the same magnification. After correction for lensing, the revised distance to SN 1997ff is m-M=45.5 mag, which improves the agreement with the Omega_M=0.35, Omega_Lambda = 0.65 cosmology expected from lower-redshift SNe Ia, and is inconsistent at the ~3 sigma confidence level with a uniform gray dust model or a simple evolution model.Comment: 5 pages, 1 figure. Final version to appear in ApJ

Galaxies in the Hubble Ultra Deep Field: I. Detection, Multiband Photometry, Photometric Redshifts, and Morphology

We present aperture-matched PSF-corrected BVi'z'JH photometry and Bayesian photometric redshifts (BPZ) for objects detected in the Hubble Ultra Deep Field (UDF), 8,042 of which are detected at the 10-sigma level (e.g., i'<29.01 or z'<28.43). Most of our objects are defined identically to those in the public STScI catalogs, enabling straightforward object-by-object comparison. We have combined detections from i', z', J+H, and B+V+i'+z' images into a single comprehensive segmentation map. Using a new program called SExSeg we are able to force this segmentation map into SExtractor for photometric analysis. The resulting photometry is corrected for the wider NIC3 PSFs using our ColorPro software. We also correct for the ACS z'-band PSF halo. The NIC3 magnitudes are found to be too faint relative to the ACS fluxes. Based on BPZ SED fits to objects of know spectroscopic redshift, we derived corrections of -0.30 +/- 0.03 mag in J and -0.18 +/- 0.04 mag in H. The offsets appear to be supported by a recent recalibration of the UDF NIC3 images combined with non-linearity measured in NICMOS itself. The UDF reveals a large population of faint blue galaxies (presumably young starbursts), bluer than those observed in the original Hubble Deep Fields (HDF). To accommodate these galaxies, we have added two new starburst templates to the SED library used in previous BPZ papers. The resulting photometric redshifts are accurate to within 0.04 * 1+z_spec out to z < 6. Finally, we measure galaxy morphology, including Sersic index and asymmetry. Our full catalog, software packages, and more are available at http://adcam.pha.jhu.edu/~coe/UDF/ (abridged)Comment: Accepted by AJ. 82 pages, 35 figures, 10 tables. At http://adcam.pha.jhu.edu/~coe/UDF/ you can find: full-resolution versions of the paper (color; B&W compact); our full catalogs and segmentation map; our SExSeg & ColorPro software packages; a clickable color image map of the UD

The Morphological Demographics of galaxies in the ACS Hubble Ultra Deep Parallel Fields

We present a morphological analysis of distant field galaxies using the deep ACS images from the public parallel NICMOS observations of the Hubble Ultra Deep Field obtained in the F435W (B), F606W (V), F775W (i) and F850LP (z) filters. We morphologically segregate galaxies using a combination of visual classification and objective machine based selection. We use the Asymmetry (A) and Central Concentration (C) parameters to characterize galaxies up to z_AB<25mag. We take advantage of the multicolor dataset and estimate redshifts for our sample using the Bayesian photometric redshift (BPZ) which enables us to investigate the evolution of their morphological demographics with redshift. Using a template fitting model and a maximum likelihood approach, we compute the star-formation rate (SFR) for galaxies up to z~1.3 and its contributions from different morphological types. We report that spirals are the main providers to the total SFR. The E/S0s contribution flattens out at z~1 while the Irr/Pec populations continuously rise to match the spirals contribution at z~1.0. We use the i-z and V-i color-magnitude diagrams to constrain the galaxies' formation histories and find that E/S0s show both a population of luminous red galaxies in place at z~1.2 and a bluer and fainter population resembling those of Irr/Pec at similar redshifts.Comment: 7 pages, 6 figures. Accepted for publication in the Astronomical Journal. Full resolution paper at: http://acs.pha.jhu.edu/~felipe/e-prints