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Cosmic Star Formation Activity at z=2.2 Probed by H-alpha Emission Line Galaxies
Cosmology and Nongalactic Astrophysics · Submitted 22 Dec 2010
abstract compiled · 2026-09-23 · no language-model review
The authors' main claim This result suggests that the timescale of galaxy formation is different among different environments, and the star forming activities in high density regions eventually overtake those in lower density regions as a consequence of "galaxy formation bias" at high redshifts.
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We present a pilot narrow-band survey of H-alpha emitters at z=2.2 in the Great Observatories Origins Deep Survey North (GOODS-N) field with MOIRCS instrument on the Subaru telescope. The survey reached a 3 sigma limiting magnitude of 23.6 (NB209) which corresponds to a 3 sigma limiting line flux of 2.5 x 10^-17 erg s^-1 cm^-2 over a 56 arcmnin^2 contiguous area (excluding a shallower area). From this survey, we have identified 11 H-alpha emitters and one AGN at z=2.2 on the basis of narrow-band excesses and photometric redshifts. We obtained spectra for seven new objects among them, including one AGN, and an emission line above 3 sigma is detected from all of them. We have estimated star formation rates (SFR) and stellar masses (M_star) for individual galaxies. The average SFR and M_star is 27.8M_solar yr^-1 and 4.0 x 10^10M_solar, respectivly. Their specific star formation rates are inversely correlated with their stellar masses. Fitting to a Schechter function yields the H-alpha luminosity function with log L = 42.82, log phi = -2.78 and alpha = -1.37. The average star formation rate density in the survey volume is estimated to be 0.31M_solar yr^-1Mpc^-3 according to the Kennicutt relation between H-alpha luminosity and star formation rate. We compare our H-alpha emitters at z=2.2 in GOODS-N with narrow-band line emitters in other field and clusters to see their time evolution and environmental dependence. We find that the star formation activity is reduced rapidly from z=2.5 to z=0.8 in the cluster environment, while it is only moderately changed in the field environment. This result suggests that the timescale of galaxy formation is different among different environments, and the star forming activities in high density regions eventually overtake those in lower density regions as a consequence of "galaxy formation bias" at high redshifts.
background contribution method result interpretation main claim
| # | sentence | role | the authors' own work | states the main conclusion | strength |
|---|---|---|---|---|---|
| s0 | We present a pilot narrow-band survey of H-alpha emitters at z=2.2 in the Great Observatories Origins Deep Survey North (GOODS-N) field with MOIRCS instrument on the Subaru telescope. | contribution 0.68 | 0.96 | 0.02 | asserted 0.97 |
| s1 | The survey reached a 3 sigma limiting magnitude of 23.6 (NB209) which corresponds to a 3 sigma limiting line flux of 2.5 x 10^-17 erg s^-1 cm^-2 over a 56 arcmnin^2 contiguous area (excluding a shallower area). | method 0.78 | 0.96 | 0.02 | asserted 1.00 |
| s2 | From this survey, we have identified 11 H-alpha emitters and one AGN at z=2.2 on the basis of narrow-band excesses and photometric redshifts. | result 0.96 | 0.98 | 0.04 | asserted 1.00 |
| s3 | We obtained spectra for seven new objects among them, including one AGN, and an emission line above 3 sigma is detected from all of them. | method 0.42 | 0.97 | 0.03 | asserted 1.00 |
| s4 | We have estimated star formation rates (SFR) and stellar masses (M_star) for individual galaxies. | contribution 0.47 | 0.97 | 0.03 | asserted 1.00 |
| s5 | The average SFR and M_star is 27.8M_solar yr^-1 and 4.0 x 10^10M_solar, respectivly. | result 1.00 | 0.95 | 0.06 | asserted 1.00 |
| s6 | Their specific star formation rates are inversely correlated with their stellar masses. | result 1.00 | 0.94 | 0.08 | asserted 1.00 |
| s7 | Fitting to a Schechter function yields the H-alpha luminosity function with log L = 42.82, log phi = -2.78 and alpha = -1.37. | result 0.99 | 0.96 | 0.05 | asserted 1.00 |
| s8 | The average star formation rate density in the survey volume is estimated to be 0.31M_solar yr^-1Mpc^-3 according to the Kennicutt relation between H-alpha luminosity and star formation rate. | result 1.00 | 0.95 | 0.07 | asserted 1.00 |
| s9 | We compare our H-alpha emitters at z=2.2 in GOODS-N with narrow-band line emitters in other field and clusters to see their time evolution and environmental dependence. | contribution 0.59 | 0.87 | 0.04 | asserted 0.76 |
| s10 | We find that the star formation activity is reduced rapidly from z=2.5 to z=0.8 in the cluster environment, while it is only moderately changed in the field environment. | result 1.00 | 0.95 | 0.49 | asserted 1.00 |
| s11 | This result suggests that the timescale of galaxy formation is different among different environments, and the star forming activities in high density regions eventually overtake those in lower density regions as a consequence of "galaxy formation bias" at high redshifts. | interpretation 1.00 | 0.52 | 0.75 | hedged possibility 1.00 |
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The paper
Original abstract
We present a pilot narrow-band survey of H-alpha emitters at z=2.2 in the Great Observatories Origins Deep Survey North (GOODS-N) field with MOIRCS instrument on the Subaru telescope. The survey reached a 3 sigma limiting magnitude of 23.6 (NB209) which corresponds to a 3 sigma limiting line flux of 2.5 x 10^-17 erg s^-1 cm^-2 over a 56 arcmnin^2 contiguous area (excluding a shallower area). From this survey, we have identified 11 H-alpha emitters and one AGN at z=2.2 on the basis of narrow-band excesses and photometric redshifts. We obtained spectra for seven new objects among them, including one AGN, and an emission line above 3 sigma is detected from all of them. We have estimated star formation rates (SFR) and stellar masses (M_star) for individual galaxies. The average SFR and M_star is 27.8M_solar yr^-1 and 4.0 x 10^10M_solar, respectivly. Their specific star formation rates are inversely correlated with their stellar masses. Fitting to a Schechter function yields the H-alpha luminosity function with log L = 42.82, log phi = -2.78 and alpha = -1.37. The average star formation rate density in the survey volume is estimated to be 0.31M_solar yr^-1Mpc^-3 according to the Kennicutt relation between H-alpha luminosity and star formation rate. We compare our H-alpha emitters at z=2.2 in GOODS-N with narrow-band line emitters in other field and clusters to see their time evolution and environmental dependence. We find that the star formation activity is reduced rapidly from z=2.5 to z=0.8 in the cluster environment, while it is only moderately changed in the field environment. This result suggests that the timescale of galaxy formation is different among different environments, and the star forming activities in high density regions eventually overtake those in lower density regions as a consequence of "galaxy formation bias" at high redshifts.
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How the literature uses it
3 arXiv papers cite this in 3 sentences
Papers citing it · 1 sentence without a confident label
Uses its data or values 1 paper
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We include compilations of ultraviolet (UV), infrared (IR), H-$α$, and 1.4GHz data from Ref. [ref] and Ref. [ref] [ Data sources and their symbols in Fig. [ref]— UV (blue): $$ [ref] , $⧫$ [ref] , $▪$ [ref] , $×$ [ref] , $⋆$ [ref] , $▴$ [ref] , $▾$ [ref] , $◂$ [ref] , $▸$ [ref] , $+$ [ref] , $$ [ref] , $∙$ [ref] , $|$ [ref] ; IR (red): $$ [ref] , $⧫$ [ref] , $▪$ [ref] , $×$ [ref] , $⋆$ [ref] , $▴$ [ref] , $▾$ [ref] ; H-$α$ (green): $$ [ref] , $⧫$ [ref] , $▪$ [ref] , $×$ [ref] ; UV+IR (cyan): $$ [ref] ; 1.4GHz (orange): $$ [ref] , $⧫$ [ref] , $▪$ [ref] .].
Quenching Global Star Formation: Dominance of Gravitational Shock Heating at z<2 · Comparison to Data · 0.84
Cites it as support 1 paper
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[ref] suggest that the star formation activity in cluster/proto-cluster may be even stronger than in the field at $z∼2$.
Properties of star-forming galaxies in a cluster and its surrounding structure at z=1.46 · Cosmic evolution of star formation activity in clusters · 0.97
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