J/ApJ/783/84 ALMA observations in 107 galaxies at z=0.2-2.5 (Scoville+, 2014)
The evolution of interstellar medium mass probed by dust emission: ALMA
observations at z = 0.3-2.
Scoville N., Aussel H., Sheth K., Scott K.S., Sanders D., Ivison R.,
Pope A., Capak P., Vanden Bout P., Manohar S., Kartaltepe J., Robertson B.,
Lilly S.
<Astrophys. J., 783, 84 (2014)>
=2014ApJ...783...84S 2014ApJ...783...84S (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, radio ; Interstellar medium ; Redshifts ; Stars, masses
Keywords: dust, extinction - evolution - galaxies: ISM - galaxies: starburst
Abstract:
The use of submillimeter dust continuum emission to probe the mass of
interstellar dust and gas in galaxies is empirically calibrated using
samples of local star-forming galaxies, Planck observations of the
Milky Way, and high-redshift submillimeter galaxies. All of these
objects suggest a similar calibration, strongly supporting the view
that the Rayleigh-Jeans tail of the dust emission can be used as an
accurate and very fast probe of the interstellar medium (ISM) in
galaxies. We present ALMA Cycle 0 observations of the Band 7 (350GHz)
dust emission in 107 galaxies from z=0.2 to 2.5. Three samples of
galaxies with a total of 101 galaxies were stellar-mass-selected from
COSMOS to have M*≃1011M☉:37 at z∼0.4, 33 at z∼0.9, and 31
at z=2. A fourth sample with six infrared-luminous galaxies at z=2 was
observed for comparison with the purely mass-selected samples. From
the fluxes detected in the stacked images for each sample, we find
that the ISM content has decreased by a factor ∼6 from 1 to
2x1010M☉ at both z=2 and 0.9 down to ∼2x109M☉at z=0.4.
The infrared-luminous sample at z=2 shows a further ∼4 times increase
in MISMcompared with the equivalent non-infrared-bright sample at
the same redshift. The gas mass fractions are ∼2%±0.5%, 12%±3%,
14%±2%, and 53%±3% for the four subsamples (z=0.4, 0.9, and 2 and
infrared-bright galaxies).
Description:
The Atacama Large Millimeter/submillimeter Array (ALMA) Cycle 0
observations for project (#2011.0. 00097.S) analyzed here were
obtained in 2012 March-October in Band 7 at 350GHz
(λ=850µm). On-source integration times were 1, 2, and 4
minutes per galaxy at z=0.3, 0.9, and 2, respectively. With continuum
bandwidths of 8GHz, the 1σ rms sensitivity was 0.5, 0.4, and
0.3mJy and typical synthesized beam sizes were ≃0.6''. The data
were calibrated and imaged with natural weighting using CASA.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table5.dat 83 37 Low-z galaxy sample in band 7
table6.dat 83 33 Mid-z galaxy sample in band 7
table7.dat 83 37 High-z galaxy sample in band 7
--------------------------------------------------------------------------------
See also:
II/284 : COSMOS Multi-Wavelength Photometry Catalog (Capak+, 2007)
J/ApJ/827/142 : ALMA observations of GKM stars in Upper Sco (Barenfeld+, 2016)
J/ApJ/812/43 : ALMA 870um obs. of HerMES galaxies (Bussmann+, 2015)
J/A+A/556/A55 : Photometry of star-forming galaxies (Ilbert+, 2013)
J/ApJ/768/91 : ALMA observations of LESS submm galaxies (Hodge+, 2013)
J/ApJ/768/74 : CO observations of star-forming galaxies (Tacconi+, 2013)
J/A+A/544/A156 : UltraVISTA Catalogue Release DR1 (McCracken+, 2012)
Byte-by-byte Description of file: table[567].dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 A9 --- Sample Galaxy sample (1)
11- 12 I2 --- Galaxy [1/37] Galaxy running sequence number (2)
14- 21 F8.4 deg RAdeg Right Ascension in decimal degrees (J2000)
23- 28 F6.4 deg DEdeg Declination in decimal degrees (J2000)
30- 33 F4.2 --- zph [0.22/2.72] Photometric redshift (3)
35- 39 F5.2 mJy Stot [-5/5] Atacama Large Millimeter/submillimeter
Array (ALMA) total integrated flux density
measurement at 850µm (Stot) (4)
41- 44 F4.2 mJy stot [0.35/2.5] Measured noise for the integrated
flux (σtot) (5)
46- 49 F4.2 mJy Speak [0.2/4.6] ALMA peak pixel flux density
measurement at 850µm (Speak) (4)
51- 54 F4.2 mJy spix [0.16/0.5] Measured noise for the peak pixel
flux (σpix) (5)
56- 60 F5.2 --- S/N [-4.7/18.3] Signal-to-Noise ratio (6)
62- 65 F4.2 10+11Msun Mass* [0.36/3.42] Stellar mass (3)
67- 71 F5.2 [Msun/yr] logSFR [-3/2.8] Log of the Star Formation Rate (3)
73 A1 --- l_Mism [<] Upper limit flag on Mism
74- 78 F5.2 10+10Msun Mism [0.8/15.1] Inferred mass of the interstellar
medium (MISM) (7)
80- 83 F4.2 10+10Msun e_Mism [0.26/3]? Error in Mism
--------------------------------------------------------------------------------
Note (1): The observed galaxies fall into four subsamples, all stellar
mass-selected but over a range of redshifts:
Low-z = z=0.22-0.48;
Mid-z = z=0.81-1.15;
High-z = z=1.46-2.54;
IR bright = InfraRed-luminous galaxy (z=1.46-2.02).
Note (2): The objects are taken from the Cosmic Evolution Survey (COSMOS)
2deg2 survey (Scoville et al. 2007ApJS..172....1S 2007ApJS..172....1S) and the galaxy
properties are from the latest photometric redshift catalog (Ilbert et al.
2013, Cat. J/A+A/556/A55). This catalog has very high accuracy photometric
redshifts based on very deep 34 band photometry, including near-IR
photometry from the Ultra-Vista survey. See Ilbert et al. 2013
(Cat. J/A+A/556/A55) for accuracy of the redshifts and the derived galaxy
stellar masses.
Note (3): The photometric redshifts and stellar masses of the galaxies are from
Ilbert et al. 2013 (Cat. J/A+A/556/A55) and the accuracy of those
quantities is discussed in detail there. The SFRs are derived from the
rest-frame UV continuum and the IR using Herschel PACS and SPIRE data, as
detailed in Scoville et al. 2013ApJS..206....3S 2013ApJS..206....3S. All of the galaxies have
greater than 10σ photometry measurements so the uncertainties in
Mass* and logSFR associated with their measurements are always less than
10%. As discussed in Ilbert et al. 2013 (Cat. J/A+A/556/A55), the
uncertainties in models used to derive the Mass* and logSFR from the
photometry are generally much larger but generally less than a factor two.
Note (4): In the images, apertures centered on the galaxy position were used to
search for significant detection of continuum in the integrated aperture
flux (Stot) or a high single pixel (Speak) within the aperture. The
former recovers instances where the emission is significantly extended
beyond the synthesized beam (≃1''); the latter is most sensitive when
the emission is unresolved. The apertures were 3'' and 2'' for the low-z
sample and the mid- and high-z samples, respectively. The aperture sizes
are intended to include most of a galactic disk (∼10kpc). A significant
detection required a 2σ S/N in the integrated aperture flux (Stot)
or a 3.6σ detection of a high single pixel (Speak) within the
aperture. These different nσ limits were chosen such that there would
be fewer than one spurious detection by either technique in the entire
sample.
Note (5): The noise estimate in both cases was from the measured dispersion in
the integrated and peak flux measurements obtained for 100 displaced
off-center apertures of the same size in each individual image.
Note (6): S/Ntot and S/Npeak calculated separately from Equation (14) and
the column S/N lists the larger in absolute magnitude of those two S/Ns; it
is the ratio of the signal in columns Stot and Speak to the measured noise
for columns Stot and Speak. Note that we let the S/N be negative in cases
where the flux estimate is negative so that several sigma negative flux
values do not end up with a positive S/N above the detection thresholds.
Note (7): Limits are given at 2σ and 3.6σ in the inferred mass,
depending on whether the better S/N was obtained for the integrated or peak
flux measurement. The detection thresholds of 2 and 3.6σ are chosen
such that the chance of a spurious "noise" detection across the entirety of
each sample is less than ∼10% (based on the measured noise in each image
and for the peak flux measurement, based on the number of pixels).
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Sylvain Guehenneux [CDS] 27-Feb-2017