This paper presents the first direct estimate of the 3D clustering properties of far-infrared sources up to z similar to 3. This has been possible thanks to the PACS Evolutionary Probe (PEP) survey ...of the GOODS-South field performed with the PACS instrument on board the Herschel satellite. 550 and 502 sources were detected respectively in the 100- and 160- mu m channels down to fluxes mJy and mJy, cuts that ensure >80 per cent completeness of the two catalogues. More than 65 per cent of these sources have an (either photometric or spectroscopic) redshift determination from the MUSIC catalogue; this percentage rises to similar to 95 per cent in the inner portion of GOODS-South which is covered by data at other wavelengths. An analysis of the deprojected two-point correlation function w(thetas) over the whole redshift range spanned by the data reports for the (comoving) correlation length, r0 similar to 6.3 and similar to 6.7Mpc, respectively at 100 and 160 mu m, corresponding to dark matter halo masses Mgap 1012.4Modot, in an excellent agreement with previous estimates obtained for mid-IR selected sources in the same field. Objects at z similar to 2 instead seem to be more strongly clustered, with r0 similar to 19 and similar to 17Mpc in the two considered PACS channels. This dramatic increase of the correlation length between z similar to 1 and similar to 2 is connected with the presence, more visible at 100 mu m than in the other band, of a wide (at least 4Mpc across in projection), Mgap 1014Modot, filamentary structure which includes more than 50 per cent of the sources detected at z similar to 2. An investigation of the properties of such sources indicates the possibility of a boosted star-forming activity in those which reside within the overdense environment with respect to more isolated galaxies found in the same redshift range. If confirmed by larger data sets, this result can be explained as due to the combined effect of large reservoirs of gas available at high redshifts in deep potential wells such as those associated with large overdensities and the enhanced rate of encounters between sources favoured by their relative proximity. Lastly, we also present our results on the evolution of the relationship between luminous and dark matter in star-forming galaxies between z similar to 1 and similar to 2. We find that the increase in (average) stellar mass in galaxies 〈 M*〉 between z similar to 1 and similar to 2 is about a factor of 10 lower than that of the dark matter haloes hosting such objects (〈 M*〉 z similar to 1/〈 M*〉 z similar to 2 similar to 4 10-1 versus Mz similar to 1halo/Mhaloz similar to 2 similar to 4 10-2). When compared with recent results taken from the literature, our findings agree with the evolutionary picture of downsizing whereby massive galaxies at z similar to 2 were more actively forming stars than their z similar to 1 counterparts, while at the same time they contained a lower fraction of their mass in the form of luminous matter.
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In order to understand which process (e.g. galactic winds, cold accretion) is responsible for the cool (T similar to 104K) halo gas around galaxies, we embarked on a programme to study the star ...formation properties of galaxies selected by their Mgii absorption signature in quasar spectra. Specifically, we searched for the H alpha line emission from galaxies near very strongzsime 2 Mgii absorbers (with rest-frame equivalent width Aa) because these could be the signposts of outflows or inflows. Surprisingly, we detect H alpha from only four hosts out of 20 sightlines (and two out of the 19 Hi-selected sightlines), despite reaching a star formation rate (SFR) sensitivity limit of 2.9Modotyr-1(5 sigma ) for a Chabrier initial mass function. This low success rate (4/20) is in contrast with ourzsime 1 survey where we detected 66 per cent (14/21) of the Mgii hosts (down to 0.6Modotyr-1; 5 sigma ). Taking into account the difference in sensitivity between the two surveys, we should have been able to detect greater than or equal to 11.4 ( greater than or equal to 7.6) of the 20zsime 2 hosts - assuming that SFR evolves as proportional to (1 +z) gamma with gamma = 2.5 (or gamma = 0) respectively - whereas we found only four galaxies. Interestingly, all thez= 2 detected hosts have observed SFRs gap 9 Modotyr-1, well above our sensitivity limit, while atz= 1 they all have SFR < 9 Modotyr-1, an evolution that is in good agreement with the evolution of the SFR main sequence, i.e. with gamma = 2.5. Moreover, we show that thez= 2 undetected hosts are not hidden under the quasar continuum after stacking our data. They also cannot be outside our surveyed area as this latter option runs against our sample selection criteria ( Aa) and the knownW lambda 2796r-impact parameter relation for low-ionization ions. Hence, strong Mgii absorbers could trace star-formation-driven winds in low-mass haloes (Mh less than or equal to 1010.6Modot), provided that the winds do not extend beyond 20kpc in order not to violate the evolution of the absorber number density dN/dz(Mgii). Alternatively, our results imply thatz= 2 galaxies traced by strong Mgii absorbers do not form stars at a rate expected (3-10Modotyr-1) for their (halo or stellar) masses, supporting the existence of a transition in accretion efficiency atMhsime 1011Modot. This scenario can explain both the detections and the non-detections.
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We present the 0.6 < z < 2.6 evolution of the ionized gas velocity dispersion in 175 star-forming disk galaxies based on data from the full \({\mathrm{KMOS}}^{3{\rm{D}}}\) integral field ...spectroscopic survey. In a forward-modeling Bayesian framework including instrumental effects and beam-smearing, we fit simultaneously the observed galaxy velocity and velocity dispersion along the kinematic major axis to derive the intrinsic velocity dispersion σ 0. We find a reduction of the average intrinsic velocity dispersion of disk galaxies as a function of cosmic time, from σ 0 ∼ 45 km s−1 at z ∼ 2.3 to σ 0 ∼ 30 km s−1 at z ∼ 0.9. There is substantial intrinsic scatter (\({\sigma }_{{\sigma }_{0},\mathrm{int}}\approx 10\,\mathrm{km}\,{{\rm{s}}}^{-1}\)) around the best-fit σ 0–z relation beyond what can be accounted for from the typical measurement uncertainties (δσ 0 ≈ 12 km s−1), independent of other identifiable galaxy parameters. This potentially suggests a dynamic mechanism such as minor mergers or variation in accretion being responsible for the scatter. Putting our data into the broader literature context, we find that ionized and atomic+molecular velocity dispersions evolve similarly with redshift, with the ionized gas dispersion being ∼10–15 km s−1 higher on average. We investigate the physical driver of the on average elevated velocity dispersions at higher redshift and find that our galaxies are at most marginally Toomre-stable, suggesting that their turbulent velocities are powered by gravitational instabilities, while stellar feedback as a driver alone is insufficient. This picture is supported through comparison with a state-of-the-art analytical model of galaxy evolution.
We exploit the deep and extended far-IR data sets (at 70, 100 and 160 μm) of the Herschel Guaranteed Time Observation (GTO) PACS Evolutionary Probe (PEP) Survey, in combination with the Herschel ...Multi-tiered Extragalactic Survey data at 250, 350 and 500 μm, to derive the evolution of the rest-frame 35-, 60-, 90- and total infrared (IR) luminosity functions (LFs) up to z ∼ 4. We detect very strong luminosity evolution for the total IR LF (L
IR ∝ (1 + z)3.55 ± 0.10 up to z ∼ 2, and ∝ (1 + z)1.62 ± 0.51 at 2 < z 4) combined with a density evolution (∝(1 + z)−0.57 ± 0.22 up to z ∼ 1 and ∝ (1 + z)−3.92 ± 0.34 at 1 < z 4). In agreement with previous findings, the IR luminosity density (ρIR) increases steeply to z ∼ 1, then flattens between z ∼ 1 and z ∼ 3 to decrease at z 3. Galaxies with different spectral energy distributions, masses and specific star formation rates (SFRs) evolve in very different ways and this large and deep statistical sample is the first one allowing us to separately study the different evolutionary behaviours of the individual IR populations contributing to ρIR. Galaxies occupying the well-established SFR-stellar mass main sequence (MS) are found to dominate both the total IR LF and ρIR at all redshifts, with the contribution from off-MS sources (≥0.6 dex above MS) being nearly constant (∼20 per cent of the total ρIR) and showing no significant signs of increase with increasing z over the whole 0.8 < z < 2.2 range. Sources with mass in the range 10 ≤ log(M/M) ≤ 11 are found to dominate the total IR LF, with more massive galaxies prevailing at the bright end of the high-z ( 2) LF. A two-fold evolutionary scheme for IR galaxies is envisaged: on the one hand, a starburst-dominated phase in which the Super Massive Black Holes (SMBH) grows and is obscured by dust (possibly triggered by a major merging event), is followed by an AGN-dominated phase, then evolving towards a local elliptical. On the other hand, moderately star-forming galaxies containing a low-luminosity AGN have various properties suggesting they are good candidates for systems in a transition phase preceding the formation of steady spiral galaxies.
Abstract In 2022 November, the James Webb Space Telescope (JWST) returned deep near-infrared images of A2744—a powerful lensing cluster capable of magnifying distant, incipient galaxies beyond it. ...Together with existing Hubble Space Telescope (HST) imaging, this publicly available data set opens a fundamentally new discovery space to understand the remaining mysteries of the formation and evolution of galaxies across cosmic time. In this work, we detect and measure some 60,000 objects across the 49 arcmin 2 JWST footprint down to a 5 σ limiting magnitude of ∼30 mag in 0.″32 apertures. Photometry is performed using circular apertures on images matched to the point-spread function (PSF) of the reddest NIRCam broad band, F444W, and cleaned of bright cluster galaxies and the related intracluster light. To give an impression of the photometric performance, we measure photometric redshifts and achieve a σ NMAD ≈ 0.03 based on known, but relatively small, spectroscopic samples. With this paper, we publicly release our HST and JWST PSF-matched photometric catalog with optimally assigned aperture sizes for easy use, along with single aperture catalogs, photometric redshifts, rest-frame colors, and individual magnification estimates. These catalogs will set the stage for efficient and deep spectroscopic follow up of some of the first JWST-selected samples in summer of 2023.
Ever deeper and wider lookback surveys have led to a fairly robust outline of the cosmic star formation history, which culminated around z~2 -- a period often nicknamed "cosmic noon." Our knowledge ...about star-forming galaxies at these epochs has dramatically advanced from increasingly complete population censuses and detailed views of individual galaxies. We highlight some of the key observational insights that influenced our current understanding of galaxy evolution in the equilibrium growth picture: \(\bullet\) scaling relations between galaxy properties are fairly well established among massive galaxies at least out to z~2, pointing to regulating mechanisms already acting on galaxy growth; \(\bullet\) resolved views reveal that gravitational instabilities and efficient secular processes within the gas- and baryon-rich galaxies at z~2 play an important role in the early build-up of galactic structure; \(\bullet\) ever more sensitive observations of kinematics at z~2 are probing the baryon and dark matter budget on galactic scales and the links between star-forming galaxies and their likely descendants; \(\bullet\) towards higher masses, massive bulges, dense cores, and powerful AGN and AGN-driven outflows are more prevalent and likely play a role in quenching star formation. We outline emerging questions and exciting prospects for the next decade with upcoming instrumentation, including the James Webb Space Telescope and the next generation of Extremely Large Telescopes.
We present near-infrared integral field observations of the super star cluster in the amorphous galaxy NGC1705. Data have been collected with SINFONI mounted on the VLT. Adaptive optics was used ...under good seeing conditions. Mosaics of the cluster and its immediate surrounding have been constructed. The cluster is not spatially resolved. Its radius is smaller than 2.85 ± 0.50pc. The K-band spectrum of the cluster is dominated by strong CO absorption bandheads. It is typical of a Galactic K 4–5 supergiant. Its age is estimated to be 12 ± 6Myr. The large error bar is rooted in the uncertainties of the input physics and ingredients of different evolutionary models.
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Deep Herschel PACS/SPIRE imaging and ... line luminosities from the IRAM Plateau de Bure Interferometer are combined for a sample of 17 galaxies at z greater than 1 from the GOODS-N field. Although ...we cannot formally distinguish between a step and a smooth evolution of ...CO with the dust temperature, the authors can unambiguously conclude that in galaxies of near-solar metallicity, a critical value of ... K can be used to determine whether the appropriate ...CO is closer to the "starburst" value or closer to the Galactic value, when ... Using ... to select the appropriate ...CO is also more indicative of ISM conditions than a fixed ... criterion. In the absence of far-infrared data, the offset of a galaxy from the star formation main sequence can be used to identify galaxies requiring the use of an ...CO conversion factor lower than the Galactic value.(ProQuest: ... denotes formulae/symbols omitted.)
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The ionisation cones of NGC5728 have a deficit of molecular gas based on millimetre observations of CO(2-1) emission. Although photoionisation from the active nucleus may lead to suppression of this ...transition, warm molecular gas can still be present. We report the detection of eight mid-infrared rotational H\(_2\) lines throughout the central kiloparsec, including the ionisation cones, using integral field spectroscopic observations with JWST/MIRI MRS. The H\(_2\) line ratios, characteristic of a power-law temperature distribution, indicate that the gas is warmest where it enters the ionisation cone through disk rotation, suggestive of shock excitation. In the nucleus, where the data can be combined with an additional seven ro-vibrational H\(_2\) transitions, we find that moderate velocity (30 km s\(^{-1}\)) shocks in dense (\(10^5\) cm\(^{-3}\)) gas, irradiated by an external UV field (\(G_0 = 10^3\)), do provide a good match to the full set. The warm molecular gas in the ionisation cone that is traced by the H\(_2\) rotational lines has been heated to temperatures \(>200\) K. Outside of the ionisation cone the molecular gas kinematics are undisturbed. However, within the ionisation cone, the kinematics are substantially perturbed, indicative of a radial flow, but one that is quantitatively different from the ionised lines. We argue that this outflow is in the plane of the disk, implying a short 50 pc acceleration zone up to speeds of about 400 km s\(^{-1}\) followed by an extended deceleration over \(\sim\)700 pc where it terminates. The deceleration is due to both the radially increasing galaxy mass, and mass-loading as ambient gas in the disk is swept up.
The broad-line region (BLR) of active galactic nuclei (AGNs) traces gas close to the central supermassive black hole (BH). Recent reverberation mapping (RM) and interferometric spectro-astrometry ...data have enabled detailed investigations of the BLR structure and dynamics, as well as estimates of the BH mass. These exciting developments motivate comparative investigations of BLR structures using different broad emission lines. In this work, we have developed a method to simultaneously model multiple broad lines of the BLR from a single-epoch spectrum. We apply this method to the five strongest broad emission lines (H\(\alpha\), H\(\beta\), H\(\gamma\), Pa\(\beta\), and He \(I\;\lambda\)5876) in the UV-to-NIR spectrum of NGC 3783, a nearby Type I AGN which has been well studied by RM and interferometric observations. Fixing the BH mass to the published value, we fit these line profiles simultaneously to constrain the BLR structure. We find that the differences between line profiles can be explained almost entirely as being due to different radial distributions of the line emission. We find that using multiple lines in this way also enables one to measure some important physical parameters, such as the inclination angle and virial factor of the BLR. The ratios of the derived BLR time lags are consistent with the expectation of theoretical model calculations and RM measurements.
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