The Hα Luminosity Function and Star Formation Rate atz≈ 0.24 in the COSMOS 2 Square Degree Field
| Autor: | A. Leauthaud, A. Nakajima, Nick Scoville, J. P. Kneib, Takashi Murayama, Y. Taniguchi, Richard Massey, Eva Schinnerer, S. J. Lilly, Patrick L. Shopbell, S. Mihara, D. B. Sanders, Masaru Ajiki, G. Hasinger, Alvio Renzini, M. Giavalisco, Jason Rhodes, H. Aussel, M. I. Takahashi, S. S. Sasaki, Y. Shioya, Y. Ideue, M. Rich, Chris Impey, Bahram Mobasher, Luigi Guzzo, Tohru Nagao, O. LeFevre |
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| Rok vydání: | 2008 |
| Předmět: |
Physics
010308 nuclear & particles physics Astronomy and Astrophysics Astrophysics Correlation function (quantum field theory) Lambda 01 natural sciences Power law Redshift Galaxy Luminosity Square degree Space and Planetary Science 0103 physical sciences 010303 astronomy & astrophysics Luminosity function (astronomy) |
| Zdroj: | The Astrophysical Journal Supplement Series. 175:128-137 |
| ISSN: | 1538-4365 0067-0049 |
| DOI: | 10.1086/523703 |
| Popis: | To derive a new H$\alpha$ luminosity function and to understand the clustering properties of star-forming galaxies at $z \approx 0.24$, we have made a narrow-band imaging survey for H$\alpha$ emitting galaxies in the HST COSMOS 2 square degree field. We used the narrow-band filter NB816 ($\lambda_c = 8150$ \AA, $\Delta \lambda = 120$ \AA) and sampled H$\alpha$ emitters with $EW_{\rm obs}(\rm H\alpha + [N\textsc{ii}]) > 12$ \AA in a redshift range between $z=0.233$ and $z=0.251$ corresponding to a depth of 70 Mpc. We obtained 980 H$\alpha$ emitting galaxies in a sky area of 5540 arcmin$^2$, corresponding to a survey volume of $3.1 \times 10^4 {\rm Mpc^3}$. We derive a H$\alpha$ luminosity function with a best-fit Schechter function parameter set of $\alpha = -1.35^{+0.11}_{-0.13}$, $\log\phi_* = -2.65^{+0.27}_{-0.38}$, and $\log L_* ({\rm erg s^{-1}}) = 41.94^{+0.38}_{-0.23}$. The H$\alpha$ luminosity density is $2.7^{+0.7}_{-0.6} \times 10^{39}$ ergs s$^{-1}$ Mpc$^{-3}$. After subtracting the AGN contribution (15 %) to the H$\alpha$ luminosity density, the star formation rate density is evaluated as $1.8^{+0.7}_{-0.4} \times 10^{-2}$ $M_{\sun}$ yr$^{-1}$ Mpc$^{-3}$. The angular two-point correlation function of H$\alpha$ emitting galaxies of $\log L({\rm H\alpha}) > 39.8$ is well fit by a power law form of $w(\theta) = 0.013^{+0.002}_{-0.001} \theta^{-0.88 \pm 0.03}$, corresponding to the correlation function of $\xi(r) = (r/1.9{\rm Mpc})^{-1.88}$. We also find that the H$\alpha$ emitters with higher H$\alpha$ luminosity are more strongly clustered than those with lower luminosity. |
| Databáze: | OpenAIRE |
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