Star formation density and H  luminosity function of an emission-line-selected galaxy sample at z  0.24

The intense study of interacting galaxies originated in large part with the discovery by IRAS that the most IR-luminous galaxies are nearly all products of collisions and may be the missing link in the chain of evolution from quasars to normal quiescent galaxies (Sanders et al. 1988a,b). These galaxies (with LIR > 1012L⊙) are considered to be the most strongly starbursting of all galaxies in the local universe, have a higher space density than quasars, emit >90% of their power in the IR, are rich in the raw materials of star formation, and to a large extent owe their peculiar morphologies to encounters with other galaxies. The particular importance of IR-luminous galaxies in the grand scheme of cosmology and galaxy evolution has been underscored by the luminosity function studies of Soifer et al. (1986), which indicated that most galaxies have gone through a high-IR luminosity stage. We are using the Hubble Space Telescope to survey the fine-scale features that are associated with the interaction- and activity-related processes that are at work within the Ultraluminous IR Galaxy Sample. It is widely believed that these galaxies are undergoing star formation at a prodigious rate and are abnormally dust-enshrouded. An alternative to the starburst hypothesis is that these galaxies' IR luminosity is powered by a dust-hidden quasar at its center (Sanders et al. 1988a). It is important for our understanding of the evolution of galaxies and quasars to determine which of these two hypotheses is valid, or in which objects they are separately valid.

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Emission Line Diagnostics of Star Formation: Nearby and at High Redshift

10.1063/1.1913915 ◽

2005 ◽

Author(s):

L. J. Kewley

Keyword(s):

Star Formation ◽

Emission Line ◽

High Redshift

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Kband SINFONI spectra of twoz~ 5 submillimeter galaxy systems: upper limits to the unobscured star formation from [O II] optical emission line searches

Astronomy and Astrophysics ◽

10.1051/0004-6361/201628952 ◽

2016 ◽

Vol 594 ◽

pp. A74 ◽

Cited By ~ 1

Author(s):

Guilherme S. Couto ◽

Luis Colina ◽

Javier Piqueras López ◽

Thaisa Storchi-Bergmann ◽

Santiago Arribas

Keyword(s):

Star Formation ◽

Emission Line ◽

Optical Emission ◽

Line Searches ◽

Upper Limits

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The completed SDSS-IV extended baryon oscillation spectroscopic survey: growth rate of structure measurement from anisotropic clustering analysis in configuration space between redshift 0.6 and 1.1 for the emission-line galaxy sample

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa3050 ◽

2020 ◽

Vol 499 (4) ◽

pp. 5527-5546 ◽

Cited By ~ 6

Author(s):

Amélie Tamone ◽

Anand Raichoor ◽

Cheng Zhao ◽

Arnaud de Mattia ◽

Claudio Gorgoni ◽

...

Keyword(s):

Growth Rate ◽

Correlation Function ◽

Emission Line ◽

Sloan Digital Sky Survey ◽

Linear Growth Rate ◽

Angular Diameter Distance ◽

Consensus Values ◽

Galaxy Sample ◽

Emission Line Galaxies ◽

Anisotropic Clustering

ABSTRACT We present the anisotropic clustering of emission-line galaxies (ELGs) from the Sloan Digital Sky Survey IV (SDSS-IV) extended Baryon Oscillation Spectroscopic Survey (eBOSS) Data Release 16 (DR16). Our sample is composed of 173 736 ELGs covering an area of 1170 deg2 over the redshift range 0.6 ≤ z ≤ 1.1. We use the convolution Lagrangian perturbation theory in addition to the Gaussian streaming redshift space distortions to model the Legendre multipoles of the anisotropic correlation function. We show that the eBOSS ELG correlation function measurement is affected by the contribution of a radial integral constraint that needs to be modelled to avoid biased results. To mitigate the effect from unknown angular systematics, we adopt a modified correlation function estimator that cancels out the angular modes from the clustering. At the effective redshift, zeff = 0.85, including statistical and systematical uncertainties, we measure the linear growth rate of structure fσ8(zeff) = 0.35 ± 0.10, the Hubble distance $D_ H(z_{\rm eff})/r_{\rm drag} = 19.1^{+1.9}_{-2.1}$, and the comoving angular diameter distance DM(zeff)/rdrag = 19.9 ± 1.0. These results are in agreement with the Fourier space analysis, leading to consensus values of: fσ8(zeff) = 0.315 ± 0.095, $D_H(z_{\rm eff})/r_{\rm drag} = 19.6^{+2.2}_{-2.1}$, and DM(zeff)/rdrag = 19.5 ± 1.0, consistent with ΛCDM model predictions with Planck parameters.

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Correlations between H α equivalent width and galaxy properties at z = 0.47: Physical or selection-driven?

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stab778 ◽

2021 ◽

Vol 503 (4) ◽

pp. 5115-5133

Author(s):

A A Khostovan ◽

S Malhotra ◽

J E Rhoads ◽

S Harish ◽

C Jiang ◽

...

Keyword(s):

Star Formation ◽

Equivalent Width ◽

Luminosity Function ◽

Mass Function ◽

Stellar Mass ◽

High Mass ◽

Selection Effects ◽

Star Formation Activity ◽

Low Mass ◽

Stellar Masses

ABSTRACT The H α equivalent width (EW) is an observational proxy for specific star formation rate (sSFR) and a tracer of episodic, bursty star-formation activity. Previous assessments show that the H α EW strongly anticorrelates with stellar mass as M−0.25 similar to the sSFR – stellar mass relation. However, such a correlation could be driven or even formed by selection effects. In this study, we investigate how H α EW distributions correlate with physical properties of galaxies and how selection biases could alter such correlations using a z = 0.47 narrow-band-selected sample of 1572 H α emitters from the Ly α Galaxies in the Epoch of Reionization (LAGER) survey as our observational case study. The sample covers a 3 deg2 area of COSMOS with a survey comoving volume of 1.1 × 105 Mpc3. We assume an intrinsic EW distribution to form mock samples of H α emitters and propagate the selection criteria to match observations, giving us control on how selection biases can affect the underlying results. We find that H α EW intrinsically correlates with stellar mass as W0∝M−0.16 ± 0.03 and decreases by a factor of ∼3 from 107 M⊙ to 1010 M⊙, while not correcting for selection effects steepens the correlation as M−0.25 ± 0.04. We find low-mass H α emitters to be ∼320 times more likely to have rest-frame EW>200 Å compared to high-mass H α emitters. Combining the intrinsic W0–stellar mass correlation with an observed stellar mass function correctly reproduces the observed H α luminosity function, while not correcting for selection effects underestimates the number of bright emitters. This suggests that the W0–stellar mass correlation when corrected for selection effects is physically significant and reproduces three statistical distributions of galaxy populations (line luminosity function, stellar mass function, EW distribution). At lower stellar masses, we find there are more high-EW outliers compared to high stellar masses, even after we take into account selection effects. Our results suggest that high sSFR outliers indicative of bursty star formation activity are intrinsically more prevalent in low-mass H α emitters and not a byproduct of selection effects.

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SDSS J114818.18-013823.7: Forming Compact Dwarf Galaxy through the Dwarf-Dwarf Merger

Journal of Nepal Physical Society ◽

10.3126/jnphyssoc.v7i2.38622 ◽

2021 ◽

Vol 7 (2) ◽

pp. 49-57

Author(s):

D. N. Chhatkuli ◽

S. Paudel ◽

A. K. Gautam ◽

B. Aryal

Keyword(s):

Star Formation ◽

Emission Line ◽

Star Formation Rate ◽

Dwarf Galaxy ◽

Formation Rate ◽

Absolute Magnitude ◽

Spectroscopic Properties ◽

Normal Galaxies ◽

Star Formation Activity ◽

The Galaxy

We studied the spectroscopic properties of the low redshift (z = 0.0130) interacting dwarf galaxy SDSS J114818.18-013823.7. It is a compact galaxy of half-light radius 521 parsec. It’s r-band absolute magnitude is -16.71 mag. Using a publicly available optical spectrum from the Sloan Sky Survey data archive, we calculated star-formation rate, emission line metallicity, and dust extinction of the galaxy. Star formation rate (SFR) due to Hα is found to be 0.118 Mʘ year-1 after extinction correction. The emission-line metallicity, 12+log(O/H), is 8.13 dex. Placing these values in the scaling relation of normal galaxies, we find that SDSS J114818.18-013823.7 is a significant outlier from both size-magnitude relation and SFR-B-band absolute relation. Although SDSS J114818.18-013823.7 possess enhance rate of star-formation, the current star-formation activity can persist several Giga years in the future at the current place and it remains compact.

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The UV Luminosity Function of Protocluster Galaxies at z ∼ 4: The Bright-end Excess and the Enhanced Star Formation Rate Density

The Astrophysical Journal ◽

10.3847/1538-4357/aba269 ◽

2020 ◽

Vol 899 (1) ◽

pp. 5

Author(s):

Kei Ito ◽

Nobunari Kashikawa ◽

Jun Toshikawa ◽

Roderik Overzier ◽

Mariko Kubo ◽

...

Keyword(s):

Star Formation ◽

Luminosity Function ◽

Star Formation Rate ◽

Formation Rate

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Low Metallicity Galaxies at z ~ 0.7: Keys to the Origins of Metallicity Scaling Laws

Proceedings of the International Astronomical Union ◽

10.1017/s1743921308025143 ◽

2008 ◽

Vol 4 (S255) ◽

pp. 397-401

Author(s):

David J. Rosario ◽

Carlos Hoyos ◽

David Koo ◽

Andrew Phillips

Keyword(s):

Star Formation ◽

Emission Line ◽

Galaxy Evolution ◽

Scaling Laws ◽

Temperature Sensitive ◽

Star Forming ◽

Low Metallicity ◽

Emission Line Galaxies ◽

Halo Masses ◽

Stellar Masses

AbstractWe present a study of remarkably luminous and unique dwarf galaxies at redshifts of 0.5 < z < 0.7, selected from the DEEP2 Galaxy Redshift survey by the presence of the temperature sensitive [OIII]λ4363 emission line. Measurements of this important auroral line, as well as other strong oxygen lines, allow us to estimate the integrated oxygen abundances of these galaxies accurately without being subject to the degeneracy inherent in the standard R23 system used by most studies. [O/H] estimates range between 1/5–1/10 of the solar value. Not surprisingly, these systems are exceedingly rare and hence represent a population that is not typically present in local surveys such as SDSS, or smaller volume deep surveys such as GOODS.Our low-metallicity galaxies exhibit many unprecedented characteristics. With B-band luminosities close to L*, thse dwarfs lie significantly away from the luminosity-metallicity relationships of both local and intermediate redshift star-forming galaxies. Using stellar masses determined from optical and NIR photometry, we show that they also deviate strongly from corresponding mass-metallicity relationships. Their specific star formation rates are high, implying a significant burst of recent star formation. A campaign of high resolution spectroscopic follow-up shows that our galaxies have dynamical properties similar to local HII and compact emission line galaxies, but mass-to-light ratios that are much higher than average star-forming dwarfs.The low metallicities, high specific star formation rates, and small halo masses of our galaxies mark them as lower redshift analogs of Lyman-Break galaxies, which, at z ~ 2 are evolving onto the metallicity sequence that we observe in the galaxy population of today. In this sense, these systems offer fundamental insights into the physical processes and regulatory mechanisms that drive galaxy evolution in that epoch of major star formation and stellar mass assembly.

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