TY - JOUR

T1 - SMM J04135+10277

T2 - a distant QSO-starburst system caught by ALMA

AU - Fogasy, Judit

AU - Knudsen, K. K.

AU - Drouart, G.

AU - Lagos, C. D. P.

AU - Fan, L.

PY - 2020/4

Y1 - 2020/4

N2 - The gas content of galaxies is a key factor for their growth, starting from star formation and black hole accretion to galaxy mergers. 'thus, characterizing its properties through observations of tracers like the CO emission line is of big importance in order to understand the bigger picture of galaxy evolution. We present Atacama Large Millimeter/submillimeter Array (ALMA) observations of dust continuum, CO(5-4) and CO(8-7) line emission in the quasar-star forming companion system SMM J04135+10277 (z = 2.84). Earlier low -J CO studies of this system found a huge molecular gas reservoir associated with the companion galaxy, while the quasar appeared gas -poor. Our CO observations revealed that the host galaxy of the quasar is also gas -rich, with an estimated molecular gas mass of - (0.7-2.3) x 1010 Mo. The CO line profiles of the companion galaxy are very broad ('- 1000 km s-1), and show signs of rotation of a compact, massive system. In contrast to previous far -infrared observations, we resolve the continuum emission and detect both sources, with the companion galaxy dominating the dust continuum and the quasar having a - 25 per cent contribution to the total dust emission. By fitting the infrared spectral energy distribution of the sources with MR-MOOSE and empirical templates, the infrared luminosities of the quasar and the companion are in the range of LIR,Qs0 "" (2.1-9.6) x 1012 Lo and Lik,comp. - (2.4-24) x 1012 L6, while the estimated star formation rates are - 210-960 and " 240-2400M yr 1, respectively. Our results demonstrate that non -detection of low-,/ CO transition lines in similar sources does not necessarily imply the absence of massive molecular gas reservoir but that the excitation conditions favour the excitation of high-./ transitions,

AB - The gas content of galaxies is a key factor for their growth, starting from star formation and black hole accretion to galaxy mergers. 'thus, characterizing its properties through observations of tracers like the CO emission line is of big importance in order to understand the bigger picture of galaxy evolution. We present Atacama Large Millimeter/submillimeter Array (ALMA) observations of dust continuum, CO(5-4) and CO(8-7) line emission in the quasar-star forming companion system SMM J04135+10277 (z = 2.84). Earlier low -J CO studies of this system found a huge molecular gas reservoir associated with the companion galaxy, while the quasar appeared gas -poor. Our CO observations revealed that the host galaxy of the quasar is also gas -rich, with an estimated molecular gas mass of - (0.7-2.3) x 1010 Mo. The CO line profiles of the companion galaxy are very broad ('- 1000 km s-1), and show signs of rotation of a compact, massive system. In contrast to previous far -infrared observations, we resolve the continuum emission and detect both sources, with the companion galaxy dominating the dust continuum and the quasar having a - 25 per cent contribution to the total dust emission. By fitting the infrared spectral energy distribution of the sources with MR-MOOSE and empirical templates, the infrared luminosities of the quasar and the companion are in the range of LIR,Qs0 "" (2.1-9.6) x 1012 Lo and Lik,comp. - (2.4-24) x 1012 L6, while the estimated star formation rates are - 210-960 and " 240-2400M yr 1, respectively. Our results demonstrate that non -detection of low-,/ CO transition lines in similar sources does not necessarily imply the absence of massive molecular gas reservoir but that the excitation conditions favour the excitation of high-./ transitions,

KW - galaxies: active

KW - galaxies: evolution

KW - galaxies: high-redshift

KW - galaxies: star-burst

KW - submillimetre: galaxies

KW - galaxies: individual: SMM J04135+10277

KW - SUPERMASSIVE BLACK-HOLES

KW - X-RAY LUMINOSITY

KW - STAR-FORMATION RATE

KW - SIMILAR-TO 2

KW - CO EMISSION

KW - SUBMILLIMETER GALAXIES

KW - HOST GALAXIES

KW - MOLECULAR GAS

KW - QUASARS

KW - EVOLUTION

U2 - 10.1093/mnras/staa472

DO - 10.1093/mnras/staa472

M3 - Journal article

VL - 493

SP - 3744

EP - 3756

JO - Royal Astronomical Society. Monthly Notices

JF - Royal Astronomical Society. Monthly Notices

SN - 0035-8711

IS - 3

ER -