TY - JOUR
T1 - Compact Starbursts in z ˜ 3-6 Submillimeter Galaxies Revealed by ALMA
AU - Ikarashi, Soh
AU - Ivison, R. J.
AU - Caputi, Karina I.
AU - Aretxaga, Itziar
AU - Dunlop, James S.
AU - Hatsukade, Bunyo
AU - Hughes, David H.
AU - Iono, Daisuke
AU - Izumi, Takuma
AU - Kawabe, Ryohei
AU - Kohno, Kotaro
AU - Lagos, Claudia D. P.
AU - Motohara, Kentaro
AU - Nakanishi, Kouichiro
AU - Ohta, Kouji
AU - Tamura, Yoichi
AU - Umehata, Hideki
AU - Wilson, Grant W.
AU - Yabe, Kiyoto
AU - Yun, Min S.
PY - 2015/9/1
Y1 - 2015/9/1
N2 - We report the source size distribution, as measured by ALMA millimetric
continuum imaging, of a sample of 13 AzTEC-selected submillimeter
galaxies (SMGs) at {z}{phot}˜ 3-6. Their infrared
luminosities and star formation rates (SFRs) are {L}{IR}˜
2-6× {10}12 {L}⊙ and
˜200-600 {M}⊙ yr-1,
respectively. The sizes of these SMGs range from 0.″10 to
0.″38, with a median of 0.″20
{}-0\buildrel{\prime\prime\over{.}
05}+0\buildrel{\prime\prime\over{.} 03} (FWHM), corresponding
to a median circularized effective radius ({R}{{c},{{e}}}) of
{0.67}-0.14+0.13 kpc, comparable to the typical
size of the stellar component measured in compact quiescent galaxies at
z˜ 2 (cQGs)—{R}{{e}}˜ 1 kpc. The median surface
SFR density of our SMGs is {100}-26+42
{M}⊙ yr-1 kpc-2,
comparable to that seen in local merger-driven (U)LIRGs rather than in
extended disk galaxies at low and high redshifts. The discovery of
compact starbursts in z≳ 3 SMGs strongly supports a massive galaxy
formation scenario wherein z˜ 3-6 SMGs evolve into the compact
stellar components of z˜ 2 cQGs. These cQGs are then thought to
evolve into the most massive ellipticals in the local universe, mostly
via dry mergers. Our results thus suggest that z≳ 3 SMGs are the
likely progenitors of massive local ellipticals, via cQGs, meaning that
we can now trace the evolutionary path of the most massive galaxies over
a period encompassing ˜90% of the age of the universe.
AB - We report the source size distribution, as measured by ALMA millimetric
continuum imaging, of a sample of 13 AzTEC-selected submillimeter
galaxies (SMGs) at {z}{phot}˜ 3-6. Their infrared
luminosities and star formation rates (SFRs) are {L}{IR}˜
2-6× {10}12 {L}⊙ and
˜200-600 {M}⊙ yr-1,
respectively. The sizes of these SMGs range from 0.″10 to
0.″38, with a median of 0.″20
{}-0\buildrel{\prime\prime\over{.}
05}+0\buildrel{\prime\prime\over{.} 03} (FWHM), corresponding
to a median circularized effective radius ({R}{{c},{{e}}}) of
{0.67}-0.14+0.13 kpc, comparable to the typical
size of the stellar component measured in compact quiescent galaxies at
z˜ 2 (cQGs)—{R}{{e}}˜ 1 kpc. The median surface
SFR density of our SMGs is {100}-26+42
{M}⊙ yr-1 kpc-2,
comparable to that seen in local merger-driven (U)LIRGs rather than in
extended disk galaxies at low and high redshifts. The discovery of
compact starbursts in z≳ 3 SMGs strongly supports a massive galaxy
formation scenario wherein z˜ 3-6 SMGs evolve into the compact
stellar components of z˜ 2 cQGs. These cQGs are then thought to
evolve into the most massive ellipticals in the local universe, mostly
via dry mergers. Our results thus suggest that z≳ 3 SMGs are the
likely progenitors of massive local ellipticals, via cQGs, meaning that
we can now trace the evolutionary path of the most massive galaxies over
a period encompassing ˜90% of the age of the universe.
KW - galaxies: evolution
KW - galaxies: formation
KW - galaxies: high-redshift
KW - submillimeter: galaxies
U2 - 10.1088/0004-637X/810/2/133
DO - 10.1088/0004-637X/810/2/133
M3 - Article
SN - 0004-637X
VL - 810
SP - 133
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2
ER -