8 research outputs found
How AGN feedback drives the size growth of the first quasars
Quasars at are powered by accretion onto supermassive black holes
with masses . Their rapid assembly
requires efficient gas inflow into the galactic nucleus, sustaining black hole
accretion at a rate close to the Eddington limit, but also high central star
formation rates. Using a set of cosmological 'zoom-in' hydrodynamic simulations
performed with the moving mesh code Arepo, we show that quasar host
galaxies develop extremely tightly bound stellar bulges with peak circular
velocities - km s and half-mass radii . Despite their high binding energy, we find that these compact bulges
expand at , with their half-mass radii reaching kpc
by . The circular velocity drops by factors from their
initial values to - km s at and the
stellar profile undergoes a cusp-core transformation. By tracking individual
stellar populations, we find that the gradual expansion of the stellar
component is mainly driven by fluctuations in the gravitational potential
induced by bursty AGN feedback. We also find that galaxy size growth and the
development of a cored stellar profile does not occur if AGN feedback is
ineffective. Our findings suggest that AGN-driven outflows may have profound
implications for the internal structure of massive galaxies, possibly
accounting for their size growth, the formation of cored ellipticals as well as
for the saturation of the - seen at high velocity
dispersions .Comment: 17 pages, 11 figures, 2 tables, accepted for publication in MNRA
Measuring the Milky Way in M-dwarfs
We report 274 M-dwarfs found in the Brightest of Reionizing Galaxies (BoRG) survey for high redshift galaxies. Using these, we fitted a model for the disk and halo with a fixed scale length at h = 2.6 kpc. We found a scale height z0 of 0.60±0.03 kpc, flattening parameter Îș of 0.45±0.04 and a powerlaw-index p of 2.4±0.07. For the total number of M-dwarfs in the disk and halo we found 26.7_(-6.2)^(+9.3)Ă10^9. The upper limit for the halo fraction of M-dwarfs in the halo is 7_(-4)^(+5) %. The total mass upper limit was determined to be 1.99_(-0.5)^(+0.73)Ă10^9 Solar masses
The size and shape of the Milky Way disc and halo from M-type brown dwarfs in the BoRG survey.
We have identified 274 M-type brown dwarfs in the Hubble Space Telescope\u27s Wide Field Camera 3 pure parallel fields from the Brightest of Reionizing Galaxies (BoRG) survey for high-redshift galaxies. These are near-infrared observations with multiple lines of sight out of our Milky Way. Using these observed M-type brown dwarfs, we fitted a Galactic disc and halo model with a Markov chain Monte Carlo analysis. This model worked best with the scalelength of the disc fixed at h = 2.6 kpc. For the scaleheight of the disc, we found z0=0.29+0.02â0.019 z0=0.29â0.019+0.02 kpc and for the central number density, Ï0=0.29+0.20â0.13 Ï0=0.29â0.13+0.20 # pcâ3. For the halo, we derived a flattening parameter Îș = 0.45 ± 0.04 and a power-law index p = 2.4 ± 0.07. We found the fraction of M-type brown dwarfs in the local density that belong to the halo to be fh = 0.0075 +0.0025â0.0019 â0.0019+0.0025 . We found no correlation between subtype of M-dwarf and any model parameters. The total number of M-type brown dwarfs in the disc and halo was determined to be 58.2+9.81â6.70Ă109 58.2â6.70+9.81Ă109 . We found an upper limit for the fraction of M-type brown dwarfs in the halo of 7 +5â4 â4+5 âperâcent. The upper limit for the total Galactic disc mass in M-dwarfs is 4.34+0.73â0.5Ă109 4.34â0.5+0.73Ă109 Mâ, assuming all M-type brown dwarfs have a mass of 80 MJ
CCDC 1429820: Experimental Crystal Structure Determination
XAJNII : Chloro-(2,4-di-t-butyl-6-((2-(diphenylphosphino)phenyl)amino)phenol)-gold(i) chloroform solvate Space Group: P 1 (2), Cell: a 9.6157(4)Ă
b 9.7984(4)Ă
c 20.5321(9)Ă
, α 85.875(2)° ÎČ 79.286(2)° Îł 63.703(2)° Related Article: DaniĂ«l L. J. Broere, Dieuwertje K. Modder, Eva Blokker, Maxime A. Siegler and Jarl Ivar van der Vlugt|2016|Angew.Chem.,Int.Ed.|55|2406|doi:10.1002/anie.201509412,An entry from the Cambridge Structural Database, the worldâs repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
CCDC 1429114: Experimental Crystal Structure Determination
XAJNEE : bis(ÎŒ2-2,4-Di-t-butyl-6-((2-(diphenylphosphino)phenyl)imino)cyclohexa-2,4-dien-1-olato radical)-gold-nickel hexafluorophosphate deuteroacetonitrile solvate Space Group: P b c a (61), Cell: a 15.6769(3)Ă
b 25.6953(6)Ă
c 31.0221(6)Ă
, α 90° ÎČ 90° Îł 90° Related Article: DaniĂ«l L. J. Broere, Dieuwertje K. Modder, Eva Blokker, Maxime A. Siegler and Jarl Ivar van der Vlugt|2016|Angew.Chem.,Int.Ed.|55|2406|doi:10.1002/anie.201509412,An entry from the Cambridge Structural Database, the worldâs repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
CCDC 1429112: Experimental Crystal Structure Determination
XAJMUT : bis(ÎŒ2-2,4-Di-t-butyl-6-((2-(diphenylphosphino)phenyl)imino)cyclohexa-2,4-dien-1-olato radical)-dichloro-di-gold-nickel dichloromethane solvate Space Group: P 1 (2), Cell: a 9.4197(3)Ă
b 13.4681(3)Ă
c 13.5232(3)Ă
, α 89.3981(19)° ÎČ 88.130(2)° Îł 71.941(2)° Related Article: DaniĂ«l L. J. Broere, Dieuwertje K. Modder, Eva Blokker, Maxime A. Siegler and Jarl Ivar van der Vlugt|2016|Angew.Chem.,Int.Ed.|55|2406|doi:10.1002/anie.201509412,An entry from the Cambridge Structural Database, the worldâs repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
CCDC 1429113: Experimental Crystal Structure Determination
XAJNAA : bis(ÎŒ2-2,4-Di-t-butyl-6-((2-(diphenylphosphino)phenyl)imino)cyclohexa-2,4-dien-1-olato radical)-dibromo-di-gold-nickel tetrahydrofuran solvate Space Group: P 21/c (14), Cell: a 13.4429(4)Ă
b 14.7209(5)Ă
c 18.3728(5)Ă
, α 90° ÎČ 106.793(3)° Îł 90° Related Article: DaniĂ«l L. J. Broere, Dieuwertje K. Modder, Eva Blokker, Maxime A. Siegler and Jarl Ivar van der Vlugt|2016|Angew.Chem.,Int.Ed.|55|2406|doi:10.1002/anie.201509412,An entry from the Cambridge Structural Database, the worldâs repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.