We have constructed a mass-selected sample of M
* > 1011 M⊙ galaxies at 1 < z < 3 in the CANDELS UKIDSS UDS and COSMOS fields and have decomposed these systems into their separate bulge and disc ...components according to their H
160-band morphologies. By extending this analysis to multiple bands, we have been able to conduct individual bulge and disc component SED fitting which has provided us with stellar-mass and star formation rate estimates for the separate bulge and disc components. Having utilized the new decomposed stellar-mass estimates, we confirm that the bulge components display a stronger size evolution than the discs. The median sizes of the bulge components is 3.09 ± 0.20 times smaller than similarly massive local galaxies over the full 1 < z < 3 redshift range; for the discs, the corresponding factor is 1.77 ± 0.10. Moreover, by splitting our sample into the passive and star-forming bulge and disc sub-populations and examining their sizes as a fraction of their present-day counter-parts, we find that the star-forming and passive bulges are equally compact, star-forming discs are larger, while the passive discs have intermediate sizes. This trend is not evident when classifying galaxy morphology on the basis of single-Sérsic fits and adopting the overall star formation rates. Finally, by evolving the star formation histories of the passive discs back to the redshifts when the passive discs were last active, we show that the passive and star-forming discs have consistent sizes at the relevant epoch. These trends need to be reproduced by any mechanisms which attempt to explain the morphological evolution of galaxies.
We investigate the evolution over the last 6.3 Gyr of cosmic time (i.e., since z- 0.7) of the average X-ray properties of early-type galaxies within the Extended Chandra Deep Field-South (E-CDF-S). ...Our early-type galaxy sample includes 539 objects with red sequence colors and Sersic indices larger than n = 2.5, which were selected jointly from the COMBO-17 (Classifying Objects by Medium-Band Observations in 17 Filters) and GEMS (Galaxy Evolution from Morphologies and SEDs) surveys. We utilize the deep Chandra observations over the E-CDF-S and X-ray stacking analyses to constrain primarily the average X-ray emission from "normal" early-type galaxies (i.e., those that are not dominated by luminous AGNs). We study separately optically luminous (L sub(B)- 10 super(10)--10 super(11)L sub(B, )) and faint (L sub(B)-10 super(9.3)-10 super(10)L sub(B, )) galaxy samples, which we expect to have soft (0.5-2.0 keV) X-ray emission dominated by hot (61 keV) interstellar gas and low-mass X-ray binary (LMXB) populations, respectively. The AGN fraction of our optically luminous sample evolves with redshift in a manner consistent with the (1 + z) super(3) evolution observed in other investigations of X-ray-selected AGNs. We find that the X-ray-to-B-band mean luminosity ratio (L sub(x)/L sub(B)) for normal optically luminous galaxies does not evolve significantly over z 6 0.0-0.7. This lack of X-ray evolution implies a general balance between the heating and cooling of the hot gas. If transient AGN activity is largely responsible for maintaining this balance, then we infer that mechanical power must be dominating the feedback out to z6 0.7. Furthermore, in this scenario the average mechanical AGN power must remain roughly constant over the last half of cosmic time. For our optically faint early-type galaxies, we find suggestive evidence that L sub(x)lL sub(B) increases with redshift over z6 0.0-0.5.
University creates unique social environments for many young people that can result in behaviour changes that can impact sexual health-related risks and facilitate transmission of HIV. Little is ...known about HIV knowledge, risk, and awareness of pre-exposure prophylaxis/post-exposure prophylaxis (PrEP/PEP) among Australian university students.
A 2019 online survey distributed through Queensland universities, using active recruitment/snowball sampling. Descriptive and logistical regression analysis investigated HIV knowledge/risk and PrEP/PEP awareness.
Of the 4,291 responses, 60.4% were 20–29 years old, 57.0% identified as heterosexual, and 31.8% were born-overseas. Mean HIV knowledge score was 9.8/12. HIV risk scores were higher among men-who-have-sex-with-men (MSM) (mean=5.2/40) compared to all other sexual behaviours (mean=3.1/40). Logistic regression indicated PrEP and PEP awareness was associated with older age (p<0.05), being non-binary/gender-diverse (p<0.05), and MSM (p<0.05). Lower odds of PrEP awareness were associated with international student status (p<0.05).
This study highlights the need for future health promotion targeting younger Australians at risk of HIV to increase uptake of PrEP/PEP, particularly among overseas-born young people and those ineligible for appropriate health care in Australia.
Addressing these gaps will improve sexual health outcomes for young Australians at risk of HIV and work towards virtual elimination of HIV transmission in Australia.
Long-acting reversible contraceptives are recommended first-line contraception; however, intrauterine device (IUD) uptake remains low in Australia.
To describe the outcomes of an independent ...evaluation of the General Practitioner IUD Insertion Network (GPIIN), a project designed to address access barriers through formalized referral pathways between general practitioners (GPs) inserting IUDs and noninserters.
An independent qualitative pragmatic inductive evaluation, involving 14 in-depth interviews with GPIIN members, was conducted 18 months post-GPIIN implementation in 2 Australian jurisdictions to identify and explore critical success factors and limitations of the model.
Local GP-to-GP IUD referral networks were considered a useful model to assist affordable and timely IUD access, improve noninserters' IUD knowledge and inserters' reflection on best practice. However, pathway simplification is needed to determine optimal integration of the concept into pragmatic GP-to-GP referral arrangements.
GPIIN provides an opportunity to improve IUD access in Primary Health Care. Further consideration of organizations best positioned and resourced to facilitate sustainable delivery and coordination is necessary.
Abstract
Mid-infrared (mid-IR) observations are powerful in identifying heavily obscured active galactic nuclei (AGN) that have weak emission in other wavelengths. Data from the Mid-Infrared ...Instrument (MIRI) on board the James Webb Space Telescope provides an excellent opportunity to perform such studies. We take advantage of the MIRI imaging data from the Cosmic Evolution Early Release Science Survey to investigate the AGN population in the distant universe. We estimate the source properties of MIRI-selected objects by utilizing spectral energy distribution (SED) modeling, and classify them into star-forming galaxies (SFs), SF-AGN mixed objects, and AGN. The source numbers of these types are 433, 102, and 25, respectively, from four MIRI pointings covering ∼9 arcmin
2
. The sample spans a redshift range of ≈0–5. We derive the median SEDs for all three source types, respectively, and publicly release them. The median MIRI SED of AGN is similar to the typical SEDs of hot dust-obscured galaxies and Seyfert 2s, for which the mid-IR SEDs are dominated by emission from AGN-heated hot dust. Based on our SED-fit results, we estimate the black hole accretion density (BHAD; i.e., total BH growth rate per comoving volume) as a function of redshift. At
z
< 3, the resulting BHAD agrees with the X-ray measurements in general. At
z
> 3, we identify a total of 27 AGN and SF-AGN mixed objects, leading to that our high-
z
BHAD is substantially higher than the X-ray results (∼0.5 dex at
z
≈ 3–5). This difference indicates MIRI can identify a large population of heavily obscured AGN missed by X-ray surveys at high redshifts.
The Spitzer Extended Deep Survey (SEDS) is a very deep infrared survey within five well-known extragalactic science fields: the UKIDSS Ultra-Deep Survey, the Extended Chandra Deep Field South, ...COSMOS, the Hubble Deep Field North, and the Extended Groth Strip. SEDS covers a total area of 1.46 deg super(2) to a depth of 26 AB mag (3sigma) in both of the warm Infrared Array Camera (IRAC) bands at 3.6 and 4.5 mum. Because of its uniform depth of coverage in so many widely-separated fields, SEDS is subject to roughly 25% smaller errors due to cosmic variance than a single-field survey of the same size. SEDS was designed to detect and characterize galaxies from intermediate to high redshifts (z = 2-7) with a built-in means of assessing the impact of cosmic variance on the individual fields. Because the full SEDS depth was accumulated in at least three separate visits to each field, typically with six-month intervals between visits, SEDS also furnishes an opportunity to assess the infrared variability of faint objects. This paper describes the SEDS survey design, processing, and publicly-available data products. Deep IRAC counts for the more than 300,000 galaxies detected by SEDS are consistent with models based on known galaxy populations. Discrete IRAC sources contribute 5.6 + or - 1.0 and 4.4 + or - 0.8 nW m super(-2) sr super(-1) at 3.6 and 4.5 mum to the diffuse cosmic infrared background (CIB). IRAC sources cannot contribute more than half of the total CIB flux estimated from DIRBE data. Barring an unexpected error in the DIRBE flux estimates, half the CIB flux must therefore come from a diffuse component.
We use data from the Pan-STARRS1 survey to present a panoramic view of the Sagittarius tidal stream in the southern Galactic hemisphere. As a result of the extensive sky coverage of Pan-STARRS1, the ...southern stream is visible along more than 60degrees of its orbit, nearly double the length seen by the Sloan Digital Sky Survey. The recently discovered southern bifurcation of the stream is also apparent, with the fainter branch of the stream visible over at least 30degrees. Using a combination of fitting both the main-sequence turnoff and the red clump, we measure the distance to both arms of the stream in the south. We find that the distances to the bright arm of the stream agree very well with the N-body models of Law & Majewski. We also find that the faint arm lies ~5 kpc closer to the Sun than the bright arm, similar to the behavior seen in the northern hemisphere.
We have compiled an extensive data set on potential parts of the Monoceros tidal stream and performed an exhaustive survey of dwarf galaxy semianalytic orbits in order to constrain its orbital ...properties. The best-fit orbits are subsequently realized as self-consistent N-body simulations in order to reproduce the spatial and velocity distribution of satellite debris. We find that all kinematic and geometric constraints can be fit by a single stream allowing for multiple wraps. The orbital eccentricity and inclination of the progenitor are strongly constrained to be e = 0.10 c 0.05 and i = 25 c 5. Ten new estimates of proper motions from the Sloan Digital Sky Survey clearly exclude all retrograde orbits. Particles lost by the satellite populate two nearly concentric rings, naturally explaining the detection of stream stars at both 6-8 kpc (Ibata et al.; Newberg et al.) and 12-18 kpc (the Tri/And stream; Rocha-Pinto et al.) from the Sun. We have attempted to predict the present location of the Monoceros stream progenitor using different information: (1) the kinematical and spatial distribution of detections, and (2) the different mean metallicity in the inner and the outer rings. Because of the lack of observational data in the whole range of Galactic latitudes, the geometrical/kinematical constraints lead to a wide range of possible locations. By associating older parts of the model stream with lower metallicity parts of the observed data, we argue in favor of a current location of l 6 245, b 6 -18, with a distance to the Sun r sub(s) 15 kpc. The mass of the progenitor has been poorly constrained because of the slow orbital decay. Similar fits have been obtained for masses (3-9) x 10 super(8) M sub( ). We have analyzed the possible common origin of the Canis Major dwarf and the Monoceros stream. The Canis Major dwarf moves on a prograde, nearly circular orbit (e 0.16) in the Milky Way disk (i 4 super(+) sub(-) super(1) sub(4) super(4) deg). This orbital inclination is too low to account for the large vertical dispersion of stream stars. However, the bimodal distribution of radial velocities in the central region found by Martin et al. probably indicates that their selection criteria for identifying dwarf stars lead to a contamination of background stars. In that case, the kinematical data outlined above might result in an underestimate of the orbital inclination. Finally, the distance estimation to Canis Major dwarf is around a factor of 2 smaller than that obtained from our model. Unfortunately, the possible identification of the Monoceros stream progenitor in Canis Major remains unclear.
Galaxies with stellar masses near M* contain the majority of stellar mass in the universe, and are therefore of special interest in the study of galaxy evolution. The Milky Way (MW) and Andromeda ...(M31) have present-day stellar masses near M*, at 5 x 10 super(10) M sub(middot in circle) (defined here to be MW-mass) and 10 super(11) M sub(middot in circle) (defined to be M31-mass). We study the typical progenitors of these galaxies using the FOURSTAR Galaxy Evolution Survey (ZFOURGE). ZFOURGE is a deep medium-band near-IR imaging survey, which is sensitive to the progenitors of these galaxies out to z ~ 3. We use abundance-matching techniques to identify the main progenitors of these galaxies at higher redshifts. We measure the evolution in the stellar mass, rest-frame colors, morphologies, far-IR luminosities, and star formation rates, combining our deep multiwavelength imaging with near-IR Hubble Space Telescope imaging from Cosmic Near-IR Deep Extragalactic Legacy Survey (CANDELS), and Spitzer and Herschel far-IR imaging from Great Observatories Origins Deep Survey-Herschel and CANDELS-Herschel. The typical MW-mass and M31-mass progenitors passed through the same evolution stages, evolving from blue, star-forming disk galaxies at the earliest stages to redder dust-obscured IR-luminous galaxies in intermediate stages and to red, more quiescent galaxies at their latest stages. The progenitors of the MW-mass galaxies reached each evolutionary stage at later times (lower redshifts) and with stellar masses that are a factor of two to three lower than the progenitors of the M31-mass galaxies. The process driving this evolution, including the suppression of star formation in present-day M* galaxies, requires an evolving stellar-mass/halo-mass ratio and/or evolving halo-mass threshold for quiescent galaxies. The effective size and SFRs imply that the baryonic cold-gas fractions drop as galaxies evolve from high redshift to z ~ 0 and are strongly anticorrelated with an increase in the Sersic index. Therefore, the growth of galaxy bulges in M* galaxies corresponds to a rapid decline in the galaxy gas fractions and/or a decrease in the star formation efficiency.
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