J/ApJ/849/2 Insights from synthetic star-forming regions. III. (Koepferl+, 2017)
Insights from synthetic star-forming regions.
III. Calibration of measurement and techniques of star formation rates.
Koepferl C.M., Robitaille T.P., Dale J.E.
<Astrophys. J., 849, 2 (2017)>
=2017ApJ...849....2K 2017ApJ...849....2K
ADC_Keywords: Star Forming Region ; Models
Keywords: methods: observational ; stars: formation ; Galaxy: stellar content ;
infrared: stars ; radiative transfer ; stars: fundamental parameters
Abstract:
Through an extensive set of realistic synthetic observations (produced
in Paper I, 2017ApJS..233....1K 2017ApJS..233....1K), we assess in this part of the paper
series (Paper III) how the choice of observational techniques affects
the measurement of star formation rates (SFRs) in star-forming
regions. We test the accuracy of commonly used techniques and
construct new methods to extract the SFR, so that these findings can
be applied to measure the SFR in real regions throughout the Milky
Way. We investigate diffuse infrared SFR tracers such as those using
24µm, 70µm and total infrared emission, which have been
previously calibrated for global galaxy scales. We set up a toy model
of a galaxy and show that the infrared emission is consistent with the
intrinsic SFR using extra-galactic calibrated laws (although the
consistency does not prove their reliability). For local scales, we
show that these techniques produce completely unreliable results for
single star-forming regions, which are governed by different
characteristic timescales. We show how calibration of these techniques
can be improved for single star-forming regions by adjusting the
characteristic timescale and the scaling factor and give suggestions
of new calibrations of the diffuse star formation tracers. We show
that star- forming regions that are dominated by high-mass stellar
feedback experience a rapid drop in infrared emission once high-mass
stellar feedback is turned on, which implies different characteristic
timescales. Moreover, we explore the measured SFRs calculated directly
from the observed young stellar population. We find that the measured
point sources follow the evolutionary pace of star formation more
directly than diffuse star formation tracers.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 80 414 Measured star-formation rates for different
time-steps and setups
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See also:
J/AJ/136/2782 : Star formation efficiency in nearby galaxies (Leroy+, 2008)
J/ApJS/181/321 : Properties of Spitzer c2d dark clouds (Evans+, 2009)
J/ApJ/692/556 : Star forming galaxy templates (Rieke+, 2009)
J/ApJ/702/178 : YSOs in the central 400pc of the Galaxy (Yusef-Zadeh+, 2009)
J/ApJ/714/1256 : Far-IR star formation rate indicators (Calzetti+, 2010)
J/ApJ/709/424 : HII regions identified with WMAPS and GLIMPSE (Murray+, 2010)
J/ApJ/733/87 : Star formation efficiency in galaxies (Shi+, 2011)
J/ApJ/799/53 : YSO/MS models in the central molecular zone (Koepferl+, 2015)
J/ApJ/841/109 : Cloud decomposition + SFR measurements (Ochsendorf+, 2017)
J/ApJ/849/1 : Insights from synthetic SF regions. II. (Koepferl+, 2017)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 7 A7 --- ID Setup identifier (1)
9- 11 I3 --- Run [24/172] Time-step number of run I
13- 17 F5.3 Myr Time [3.5/6.9] Time
19- 26 E8.2 Msun/yr SFR1 [2.2e-09/2.1e-07] Intrinsic simulations
star-formation rate convolved with a 100Myr
characteristic timescale
28- 35 E8.2 Msun/yr SFR2 [1.4e-08/0.0005] Measured star-formation rate
from synthetic 24um observations
with background B1
37- 44 E8.2 Msun/yr SFR3 [1.1e-05/0.0005] Measured star-formation rate
from synthetic 24um observations
with background B2
46- 53 E8.2 Msun/yr SFR4 [1e-06/5.8e-05] Measured star-formation rate
from synthetic 70um observations
with background B1
55- 62 E8.2 Msun/yr SFR5 [1.4e-05/10e-05] Measured star-formation rate
from synthetic 70um observations
with background B2
64- 71 E8.2 Msun/yr SFR6 [9.9e-07/0.0002] Measured star-formation rate
from synthetic total infrared observations
with background B1
73- 80 E8.2 Msun/yr SFR7 [3.6e-05/0.0003] Measured star-formation rate
from synthetic total infrared observations
with background B2
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Note (1):
Circumstellar values:
CM1 = no refinement;
CM2 = refinement with rotationally flattened envelope;
CM3 = refinement with power-law envelope.
Orientations:
O1 = xy plane
O2 = xz plane;
O3 = yz plane.
Distances:
D1 = 3 kpc;
D2 = 10 kpc.
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History:
From electronic version of the journal
References:
Koepferl et al. Paper I. 2017ApJS..233....1K 2017ApJS..233....1K
Koepferl et al. Paper II. 2017ApJ...849....1K 2017ApJ...849....1K Cat. J/ApJ/849/2
Koepferl et al. Paper III. 2017ApJ...849....2K 2017ApJ...849....2K This catalog
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 13-Jun-2018