67 research outputs found
Jansky Very Large Array detections of CO(1-0) emission in HI-absorption-selected galaxies at
We report a Karl G. Jansky Very Large Array search for redshifted CO(1-0)
emission from three HI-absorption-selected galaxies at ,
identified earlier in their CO(3-2) or CO(4-3) emission. We detect CO(1-0)
emission from DLA B1228-113 at and DLA J0918+1636 at
; these are the first detections of CO(1-0) emission in
high- HI-selected galaxies. We obtain high molecular gas masses, , for the two
objects with CO(1-0) detections, which are a factor of lower
than earlier estimates. We determine the excitation of the mid CO
rotational levels relative to the level, r, in HI-selected
galaxies for the first time, obtaining r and r for DLA J0918+1636, and r for DLA
B1228-113. These values are consistent with thermal excitation of the
levels. The excitation of the level in the HI-selected galaxies is
similar to that seen in massive main-sequence and sub-mm galaxies at
, but higher than that in main-sequence galaxies at ;
the higher excitation of the galaxies at is likely to be due to
their higher star-formation rate (SFR) surface density. We use Hubble Space
Telescope Wide Field Camera 3 imaging to detect the rest-frame near-ultraviolet
emission of DLA B1228-113, obtaining an NUV SFR of M
yr, significantly lower than that obtained from the total infrared
luminosity, indicating significant dust extinction in the
galaxy.Comment: 9 pages, 4 figures, and 2 tables. Accepted for publication in ApJ
An additive subfamily of enlargements of a maximally monotone operator
We introduce a subfamily of additive enlargements of a maximally monotone
operator. Our definition is inspired by the early work of Simon Fitzpatrick.
These enlargements constitute a subfamily of the family of enlargements
introduced by Svaiter. When the operator under consideration is the
subdifferential of a convex lower semicontinuous proper function, we prove that
some members of the subfamily are smaller than the classical
-subdifferential enlargement widely used in convex analysis. We also
recover the epsilon-subdifferential within the subfamily. Since they are all
additive, the enlargements in our subfamily can be seen as structurally closer
to the -subdifferential enlargement
Challenges and Techniques for Simulating Line Emission
Modeling emission lines from the millimeter to the UV and producing synthetic spectra is crucial for a good understanding of observations, yet it is an art filled with hazards. This is the proceedings of “Walking the Line”, a 3-day conference held in 2018 that brought together scientists working on different aspects of emission line simulations, in order to share knowledge and discuss the methodology. Emission lines across the spectrum from the millimeter to the UV were discussed, with most of the focus on the interstellar medium, but also some topics on the circumgalactic medium. The most important quality of a useful model is a good synergy with observations and experiments. Challenges in simulating line emission are identified, some of which are already being worked upon, and others that must be addressed in the future for models to agree with observations. Recent advances in several areas aiming at achieving that synergy are summarized here, from micro-physical to galactic and circum-galactic scale
Metal line emission from galaxy haloes at z~1
We present a study of the metal-enriched halo gas, traced using MgII and
[OII] emission lines, in two large, blind galaxy surveys - the MUSE (Multi Unit
Spectroscopic Explorer) Analysis of Gas around Galaxies (MAGG) and the MUSE
Ultra Deep Field (MUDF). By stacking a sample of ~600 galaxies (stellar masses
M* ~10^{6-12} Msun), we characterize for the first time the average metal line
emission from a general population of galaxy haloes at 0.7 <= z <= 1.5. The
MgII and [OII] line emission extends farther out than the stellar continuum
emission, on average out to ~25 kpc and ~45 kpc, respectively, at a surface
brightness (SB) level of 10^{-20} erg/s/cm2/arcsec2. The radial profile of the
MgII SB is shallower than that of the [OII], suggesting that the resonant MgII
emission is affected by dust and radiative transfer effects. The [OII] to MgII
SB ratio is ~3 over ~20-40 kpc, also indicating a significant in situ origin of
the extended metal emission. The average SB profiles are intrinsically brighter
by a factor ~2-3 and more radially extended by a factor of ~1.3 at 1.0 < z <=
1.5 than at 0.7 <= z <= 1.0. The average extent of the metal emission also
increases independently with increasing stellar mass and in overdense group
environments. When considering individual detections, we find extended [OII]
emission up to ~50 kpc around ~30-40 percent of the group galaxies, and
extended (~30-40 kpc) MgII emission around two z~1 quasars in groups, which
could arise from outflows or environmental processes.Comment: 24 pages, 21 figures, 2 tables, accepted for publication in MNRA
Hubble Space Telescope Observations of [O~III] Emission in Nearby QSO2s: Physical Properties of the Ionised Outflows
We use Hubble Space Telescope (HST)/ Space Telescope Imaging Spectrograph
(STIS) long-slit G430M and G750M spectra to analyse the extended [O~III] 5007A
emission in a sample of twelve nearby (z 1.6 x 10^45
erg s^-1) QSO2s. The purpose of the study is to determine the properties of the
mass outflows of ionised gas and their role in AGN feedback. We measure fluxes
and velocities as functions of radial distances. Using Cloudy models and
ionising luminosities derived from [O~III] 5007A, we are able to estimate the
densities for the emission-line gas. From these results, we derive masses of
[O~III]-emitting gas, mass outflow rates, kinetic energies, kinetic
luminosities, momenta and momentum flow rates as a function of radial distance
for each of the targets. For the sample, masses are several times 10^3 - 10^7
solar masses and peak outflow rates are 9.3 x 10^-3 Msun/yr to 10.3 Msun/yr.
The peak kinetic luminosities are 3.4 x 10^-8 to 4.9 x 10^-4 of the bolometric
luminosity, which does not approach the 5.0 x 10^-3 - 5.0 x 10^-2 range
required by some models for efficient feedback. For Mrk 34, which has the
largest kinetic luminosity of our sample, in order to produce efficient
feedback there would have to be 10 times more [O~III]-emitting gas than we
detected at its position of maximum kinetic luminosity. Three targets show
extended [O~III] emission, but compact outflow regions. This may be due to
different mass profiles or different evolutionary histories.Comment: 14 pages, 11 Figures, accepted for publication in the MNRA
The AGNIFS survey: spatially resolved observations of hot molecular and ionised outflows in nearby active galaxies
We present the hot molecular and warm ionised gas kinematics for 33 nearby
() X-ray selected active galaxies using the Hm and Br emission lines observed in the K-band with the
Gemini Near-Infrared Field Spectrograph (NIFS). The observations cover the
inner 0.042 kpc of each AGN at spatial resolutions of 4250 pc with a
velocity resolution of 20 . We find
that 31 objects (94 per cent) present a kinematically disturbed region (KDR)
seen in ionised gas, while such regions are observed in hot molecular gas for
25 galaxies (76 per cent). We interpret the KDR as being due to outflows with
masses of 1010 M and 1010 M for the ionised
and hot molecular gas, respectively. The ranges of mass-outflow rates
() and kinetic power () of the outflows are
1010 Myr and 1010 erg
s for the ionised gas outflows, and 1010 M
yr and 1010 erg s for the hot molecular gas
outflows. The median coupling efficiency in our sample is and the estimated momentum fluxes of the outflows
suggest they are produced by radiation-pressure in low-density environment,
with possible contribution from shocks.Comment: 37 pages, published in MNRAS - A few typos in the text and in the
label of Fg 1 were corrected in this versio
- …