TY - JOUR
T1 - Host galaxies of high-redshift extremely red and obscured quasars
AU - Zakamska, Nadia L.
AU - Sun, Ai Lei
AU - Strauss, Michael A.
AU - Alexandroff, Rachael M.
AU - Brandt, W. N.
AU - Chiaberge, Marco
AU - Greene, Jenny E.
AU - Hamann, Fred
AU - Liu, Guilin
AU - Perrotta, Serena
AU - Ross, Nicholas P.
AU - Wylezalek, Dominika
N1 - Publisher Copyright:
© 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society
PY - 2019/10/11
Y1 - 2019/10/11
N2 - We present Hubble Space Telescope 1.4-1.6 μm images of the hosts of 10 extremely red quasars (ERQs) and six type 2 quasar candidates at z = 2-3. ERQs, whose bolometric luminosities range between 1047 and 1048 erg s−1, show spectroscopic signs of powerful ionized winds, whereas type 2 quasar candidates are less luminous and show only mild outflows. After performing careful subtraction of the quasar light, we clearly detect almost all host galaxies. The median rest-frame B-band luminosity of the ERQ hosts in our sample is 1011.2 L☉, or ∼4L∗ at this redshift. Two of the 10 hosts of ERQs are in ongoing mergers. The hosts of the type 2 quasar candidates are 0.6 dex less luminous, with 2/6 in likely ongoing mergers. Intriguingly, despite some signs of interaction and presence of low-mass companions, our objects do not show nearly as much major merger activity as do high-redshift radio-loud galaxies and quasars. In the absence of an overt connection to major ongoing gas-rich merger activity, our observations are consistent with a model in which the near-Eddington accretion and strong feedback of ERQs are associated with relatively late stages of mergers resulting in early-type remnants. These results are in some tension with theoretical expectations of galaxy formation models, in which rapid black hole growth occurs within a short time of a major merger. Type 2 quasar candidates are less luminous, so they may instead be powered by internal galactic processes.
AB - We present Hubble Space Telescope 1.4-1.6 μm images of the hosts of 10 extremely red quasars (ERQs) and six type 2 quasar candidates at z = 2-3. ERQs, whose bolometric luminosities range between 1047 and 1048 erg s−1, show spectroscopic signs of powerful ionized winds, whereas type 2 quasar candidates are less luminous and show only mild outflows. After performing careful subtraction of the quasar light, we clearly detect almost all host galaxies. The median rest-frame B-band luminosity of the ERQ hosts in our sample is 1011.2 L☉, or ∼4L∗ at this redshift. Two of the 10 hosts of ERQs are in ongoing mergers. The hosts of the type 2 quasar candidates are 0.6 dex less luminous, with 2/6 in likely ongoing mergers. Intriguingly, despite some signs of interaction and presence of low-mass companions, our objects do not show nearly as much major merger activity as do high-redshift radio-loud galaxies and quasars. In the absence of an overt connection to major ongoing gas-rich merger activity, our observations are consistent with a model in which the near-Eddington accretion and strong feedback of ERQs are associated with relatively late stages of mergers resulting in early-type remnants. These results are in some tension with theoretical expectations of galaxy formation models, in which rapid black hole growth occurs within a short time of a major merger. Type 2 quasar candidates are less luminous, so they may instead be powered by internal galactic processes.
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U2 - 10.1093/mnras/stz2071
DO - 10.1093/mnras/stz2071
M3 - Article
AN - SCOPUS:85081554822
SN - 0035-8711
VL - 489
SP - 497
EP - 516
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 1
ER -