J/ApJ/846/105 [CII], [OI] and [OIII] line emission from z∼6 gal. (Olsen+, 2017)
SIGAME simulations of the [CII], [OI] and [OIII] line emission from star-forming
galaxies at z∼6.
Olsen K., Greve T.R., Narayanan D., Thompson R., Dave R., Rios L.N.,
Stawinski S.
<Astrophys. J., 846, 105 (2017)>
=2017ApJ...846..105O 2017ApJ...846..105O
ADC_Keywords: Galaxies, IR ; Redshifts ; Interstellar medium ;
Millimetric/submm sources
Keywords: cosmology: theory; galaxies: high-redshift; galaxies: ISM;
line: formation; methods: numerical; submillimeter: ISM
Abstract:
Of the almost 40 star-forming galaxies at z≳5 (not counting
quasi-stellar objects) observed in [CII] to date, nearly half are
either very faint in [CII] or not detected at all, and fall well below
expectations based on locally derived relations between star formation
rate and [CII] luminosity. This has raised questions as to how
reliable [CII] is as a tracer of star formation activity at these
epochs and how factors such as metallicity might affect the [CII]
emission. Combining cosmological zoom simulations of galaxies with
SIGAME (SImulator of GAlaxy Millimeter/submillimeter Emission), we
modeled the multiphased interstellar medium (ISM) and its emission in
[CII], as well as in [OI] and [OIII], from 30 main-sequence galaxies
at z∼6 with star formation rates ∼3-23M☉/yr, stellar masses
~(0.7-8)x109M☉, and metallicities ~(0.1-0.4)xZ☉. The
simulations are able to reproduce the aforementioned [CII] faintness
of some normal star-forming galaxy sources at z≥5. In terms of [OI]
and [OIII], very few observations are available at z≳5, but our
simulations match two of the three existing z≳5 detections of [OIII]
and are furthermore roughly consistent with the [OI] and [OIII]
luminosity relations with star formation rate observed for local
starburst galaxies. We find that the [CII] emission is dominated by
the diffuse ionized gas phase and molecular clouds, which on average
contribute ∼66% and ∼27%, respectively. The molecular gas, which
constitutes only ∼10% of the total gas mass, is thus a more efficient
emitter of [CII] than the ionized gas, which makes up ∼85% of the
total gas mass. A principal component analysis shows that the [CII]
luminosity correlates with the star formation activity of a galaxy as
well as its average metallicity. The low metallicities of our
simulations together with their low molecular gas mass fractions can
account for their [CII] faintness, and we suggest that these factors
may also be responsible for the [CII]-faint normal galaxies observed
at these early epochs.
Description:
We use cosmological zoom simulations of galaxies extracted from the
MUFASA cosmological simulation (Dave+ 2016MNRAS.462.3265D 2016MNRAS.462.3265D,
2017MNRAS.467..115D 2017MNRAS.467..115D); see section 2.
For the purposes of this paper, we updated SIGAME from the version
presented in Olsen+ (2015ApJ...814...76O 2015ApJ...814...76O); see section 3.
Throughout, we adopt a flat cold dark matter (ΛCDM) cosmology
with cosmological parameters ΩΛ=0.7, ΩM=0.3,
and h=0.68.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 110 37 All [CII] observations in the literature
to date of z>5
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See also:
J/ApJS/178/280 : Compendium of ISO far-IR extragalactic data (Brauher+, 2008)
J/ApJ/774/68 : [CII]157.7um feature in LIRGs (Diaz-Santos+, 2013)
J/ApJ/820/83 : ALMA galaxy properties in COSMOS field (Scoville+, 2016)
J/ApJ/844/171 : Lyα profile in 43 Green Pea galaxies (Yang+, 2017)
J/ApJ/845/96 : [CII] emission in the ISM of nearby galaxies (Croxall+, 2017)
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 20 A20 --- Name Name of object
22- 27 F6.4 --- z [5.1/7.7] Spectroscopic redshift
29 A1 --- l_SFR The 3σ upper limit flag on SFR
30- 35 F6.2 Msun/yr SFR [0.4/750] Star Formation Rate (1)
37- 42 F6.2 Msun/yr hiSFR [0.4/376]? High Star Formation Rate (2)
44 A1 --- l_LCII The 3σ upper limit flag on LCII
45- 53 E9.3 Lsun LCII [300000/16200000000] The [CII]157.7um
luminosity (3)
55 A1 --- l_Mag The 3σ upper limit flag on Mag
56- 61 F6.2 --- Mag [1/100] Lensing magnification;
1 where not known
63 I1 --- n_SFR [1/4] Note on SFR (4)
65- 90 A26 --- Ref Reference (Author, year)
92-110 A19 --- BibCode Bibcode
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Note (1): Converted to Chabrier IMF.
Note (2): High SFR in cases where two were derived, see flag "2" in n_SFR.
Note (3): Corrected for gravitational magnification.
Note (4): Note as follows:
1 = SED-based SFR.
2 = Low SFRs are derived from the UV; high SFRs are from the UV combined
with an upper limit in the IR.
3 = UV-based SFR.
4 = IR-based SFR.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 22-May-2018