J/ApJ/931/16 Galaxy Zoo: Clump Scout: clumpy SDSS gal. at z~<0.2 (Adams+, 2022)
Galaxy Zoo: Clump Scout: Surveying the Local Universe for Giant Star-forming
Clumps.
Adams D., Mehta V., Dickinson H., Scarlata C., Fortson L., Kruk S.,
Simmons B., Lintott C.
<Astrophys. J., 931, 16 (2022)>
=2022ApJ...931...16A 2022ApJ...931...16A
ADC_Keywords: Galaxies, optical; Morphology; Redshifts; Photometry, SDSS;
Star Forming Region
Keywords: Starburst galaxies ; Galaxies ; Galaxy evolution ; Galaxy formation ;
Galaxy structure ; Cosmological evolution
Abstract:
Massive, star-forming clumps are a common feature of high-redshift
star-forming galaxies. How they formed, and why they are so rare at
low redshift, remains unclear. In this paper we identify the largest
sample yet of clumpy galaxies (7050) at low redshift using data from
the citizen science project Galaxy Zoo: Clump Scout, in which
volunteers classified 58550 Sloan Digital Sky Survey (SDSS) galaxies
spanning redshift 0.02<z<0.15. We apply a robust completeness
correction by comparing with simulated clumps identified by the same
method. Requiring that the ratio of clump to galaxy flux in the SDSS u
band be greater than 8% (similar to clump definitions used by other
works), we estimate the fraction of local star-forming galaxies
hosting at least one clump (fclumpy) to be 3.22-0.34+0.38%. We
also compute the same fraction with a less stringent relative flux cut
of 3% (12.68-0.88+1.38%), as the higher number count and lower
statistical noise of this fraction permit finer comparison with future
low-redshift clumpy galaxy studies. Our results reveal a sharp decline
in fclumpy over 0<z<0.5. The minor merger rate remains roughly
constant over the same span, so we suggest that minor mergers are
unlikely to be the primary driver of clump formation. Instead, the
rate of galaxy turbulence is a better tracer for fclumpy over 0<z<1.5
for galaxies of all masses, which supports the idea that clump
formation is primarily driven by violent disk instability for all
galaxy populations during this period.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table3.dat 367 14596 *Clump Scout catalog
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Note on table3.dat: References abbreviated as "SDSS" refer to the SDSS DR15
catalog (York+ 2000AJ....120.1579Y 2000AJ....120.1579Y), while those abbreviated as
"MPA-JHU" refer to the value-added catalog released with SDSS, based
on work by Kauffmann+ 2003MNRAS.341...33K 2003MNRAS.341...33K and
Brinchmann+ 2004MNRAS.351.1151B 2004MNRAS.351.1151B
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See also:
II/306 : The SDSS Photometric Catalog, Release 8 (Adelman-McCarthy+, 2011)
V/154 : Sloan Digital Sky Surveys (SDSS), Release 16 (DR16) (Ahumada+, 2020)
J/ApJ/428/693 : Rosette Nebula & Maddalena Cloud structures (Williams+ 1994)
J/MNRAS/435/2835 : Morphological types from Galaxy Zoo 2 (Willett+, 2013)
J/other/NatAs/2.76 : MACSJ1206.2-08474714 clumps photometry (Cava+, 2018)
J/ApJ/853/108 : Clumpy galaxies in CANDELS. II. 0.5≤z<3.0 (Guo+, 2018)
J/MNRAS/489/2792 : Clumps and satellites impact on galaxy mass (Zanella+, 2019)
J/ApJ/912/49 : Clumps in z<0.06 SDSS Stripe 82 sample (Mehta+, 2021)
http://z.umn.edu/ClumpScout : Clump Scout homepage on Galaxy Zoo
http://wwwmpa.mpa-garching.mpg.de/SDSS/DR7/ : MPA-JHU homepage
Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 19 I19 --- objID SDSS DR8 object identifier
21 I1 --- Index [1/8] Clump index
23- 29 A7 --- Sample Galaxy sample
("regular":14268 occurrences or "extra")
31- 36 F6.4 --- z [0.02/0.25] SDSS Galaxy redshift
38- 47 F10.6 deg RAdeg SDSS Galaxy Right Ascension (J2000)
49- 57 F9.6 deg DEdeg [-3.4/69.1] SDSS Galaxy Declination
(J2000)
59- 64 F6.4 arcsec rFWHM [0.6/2.1] SDSS Galaxy image r-band
PSF-FWHM
66- 71 F6.1 uJy uGFlux [0/5487] SDSS Galaxy u-band flux
73- 78 F6.1 uJy e_uGFlux [0/4432] Uncertainty in uGFlux
80- 86 F7.1 uJy gGFlux [0/20501.2] SDSS Galaxy g-band flux
88- 93 F6.1 uJy e_gGFlux [0/3231] Uncertainty in gGFLux
95- 101 F7.1 uJy rGFlux [0/43581] SDSS Galaxy r-band flux
103- 108 F6.1 uJy e_rGFlux [0/2686] Uncertainty in rGFLux
110- 116 F7.1 uJy iGFlux [0/62418] SDSS Galaxy i-band flux
118- 123 F6.1 uJy e_iGFlux [0/4210] Uncertainty in iGFLux
125- 131 F7.1 uJy zGFlux [0/78416] SDSS Galaxy z-band flux
133- 139 F7.1 uJy e_zGFlux [0/12019] Uncertainty in zGFLux
141- 150 F10.6 deg RABdeg Central bulge Right Ascension (J2000)
152- 160 F9.6 deg DEBdeg [-3.4/69.1] Central bulge Declination
(J2000)
162- 168 F7.3 arcsec reff [0.001/150] SDSS Galaxy r-band effective
radius
170- 174 F5.2 [Msun] logMs [7.2/12.4] MPA-JHU log galactic stellar
mass
176- 183 F8.2 [Msun/Gyr] logSFR [-9981/12] MPA-JHU log galactic star
formation rate
185- 192 F8.2 [Gyr-1] logsSFR [-9990/1.8] MPA-JHU log galactic
specific star formation rate
194- 203 F10.6 deg RACdeg Clump Right Ascension (J2000)
205- 213 F9.6 deg DECdeg [-3.4/69.1] Clump Declination (J2000)
215- 219 F5.2 arcsec Offset [1/62] Clump offset from central bulge
221- 227 F7.2 uJy uCFlux [-6.1/3137] Clump u-band flux
229- 232 F4.2 uJy e_uCFlux [0.8/9] Uncertainty in uCFlux
234- 241 F8.2 uJy gCFlux [-12.7/10099] Clump g-band flux
243- 246 F4.2 uJy e_gCFlux [0.3/7] Uncertainty in gCFlux
248- 255 F8.2 uJy rCFlux [-14.1/14931] Clump r-band flux
257- 260 F4.2 uJy e_rCFlux [0.5/9] Uncertainty in rCFlux
262- 269 F8.2 uJy iCFlux [-15.4/16814] Clump i-band flux
271- 274 F4.2 uJy e_iCFlux [0.7/10] Uncertainty in iCFlux
276- 283 F8.2 uJy zCFlux [-24.6/25762] Clump z-band flux
285- 289 F5.2 uJy e_zCFlux [2.6/29] Uncertainty in zCFlux
291- 295 F5.2 uJy/arcsec2 uBFlux [-0.3/26] Background u-band flux
297- 300 F4.2 uJy/arcsec2 e_uBFlux [0.7/3] Uncertainty in uBFlux
302- 306 F5.2 uJy/arcsec2 gBFlux [-0/63.5] Background g-band flux
308- 311 F4.2 uJy/arcsec2 e_gBFlux [0.3/1.3] Uncertainty in gBFlux
313- 317 F5.2 uJy/arcsec2 rBFlux [0/61] Background r-band flux
319- 322 F4.2 uJy/arcsec2 e_rBFlux [0.5/1.5] Uncertainty in rBFlux
324- 328 F5.2 uJy/arcsec2 iBFlux [-0.01/87] Background i-band flux
330- 333 F4.2 uJy/arcsec2 e_iBFlux [0.7/2] Uncertainty in iBFlux
335- 340 F6.2 uJy/arcsec2 zBFlux [-0.9/112] Background z-band flux
342- 345 F4.2 uJy/arcsec2 e_zBFlux [2.4/7.1] Uncertainty in zBFlux
347- 355 F9.3 --- fLu [0/50319]? Estimated clump/galaxy
near-UV flux ratio
357- 360 F4.2 --- Frac [0/1] Volunteer unusual fraction
362 I1 --- Pec [0/1] Unusual flag (1=true)
364- 367 F4.2 --- Comp [0.01/0.9]? Completeness estimate
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 20-Mar-2024