The fourth data release of the Kilo-Degree Survey: <i>ugri</i> imaging and nine-band optical-IR photometry over 1000 square degrees

Kuijken, Konrad; Heymans, Catherine; Dvornik, Andrej; Hildebrandt, Hendrik; Jong, J. T. A. de; Wright, Angus H.; Erben, T.; Bilicki, Maciej; Giblin, Benjamin; Shan, Huanyuan; Getman, F.; Grado, A.; Hoekstra, Henk; Miller, L.; Napolitano, N. R.; Paolilo, M.; Radovich, M.; Schneider, Peter; Sutherland, William J.; Tewes, M.; Tortora, C.; Valentijn, E. A.; Kleijn, G. A. Verdoes

doi:10.1051/0004-6361/201834918

Cited by 282 publications

(342 citation statements)

References 69 publications

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“…The constraints on all fitted parameters are shown in Fig. A.2 and the corresponding best-fit values and means are shown alongside their 68% 18 The correlation matrix Corr is obtained from the covariance matrix C as Corrij = C ij/ C ii C jj . confidence limits in Tab.…”

Section: Fiducial Constraintsmentioning

confidence: 99%

Tomographic galaxy clustering with the Subaru Hyper Suprime-Cam first year public data release

Nicola

Alonso

Sánchez

et al. 2020

J. Cosmol. Astropart. Phys.

101

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We analyze the clustering of galaxies in the first public data release of the Hyper Suprime-Cam Subaru Strategic Program. Despite the relatively small footprints of the observed fields, the data are an excellent proxy for the very deep photometric datasets that will be acquired by the Large Synoptic Survey Telescope, and are therefore an ideal test bed for the analysis methods being implemented by the LSST Dark Energy Science Collaboration. We select a magnitude limited sample with i < 24.5 and analyze it in four tomographic redshift bins covering the range 0.15 z 1.5. We carry out a Fourier-space analysis of the two-point clustering of this sample, including all auto-and cross-correlations between bins. We demonstrate the use of map-level deprojection methods to account for non-physical fluctuations in the galaxy number density caused by observational systematics. Through a halo occupation distribution analysis, we place constraints on the characteristic halo masses of this sample as a function of redshift, finding a good fit up to scales k max = 1 Mpc −1 , including both auto-and cross-correlations. Our results show monotonically decreasing average halo masses with increasing redshift, which can be interpreted in terms of the drop-out of red galaxies at high redshifts for a flux-limited sample, consistent with previous analyses. In terms of photometric redshift systematics, we show that additional care is needed in order to marginalize over uncertainties in the redshift distribution in galaxy clustering, even for samples of this small size, and that these uncertainties can be significantly constrained by including cross-bin correlations. We are able to make a ∼ 3σ detection of the effects of lensing magnification in the HSC data. Our results are stable to variations in the amplitude of density fluctuations σ 8 and the cold dark matter abundance Ω c and we find constraints that agree well with measurements from Planck and low-redshift probes. Finally, we use our analysis pipeline to study the clustering of galaxies as a function of limiting flux, and provide a simple fitting function for the linear galaxy bias for magnitude limited samples as a function of limiting magnitude and redshift. Discussion and Conclusions 50A Reconstructing depth from discrete sources 54

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Section: Fiducial Constraintsmentioning

confidence: 99%

Tomographic galaxy clustering with the Subaru Hyper Suprime-Cam first year public data release

Nicola

Alonso

Sánchez

et al. 2020

J. Cosmol. Astropart. Phys.

101

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“…Using ASKAP we have detected H I absorption at z = 0.3562 in the galaxy GAMA J224500.05−343031.7. In Figure 9 we show a three-colour optical image of this galaxy using gri-band images from Data Release 4 of the VST Kilo-Degree Survey (KiDS; Kuijken et al 2019). The catalogued position of the radio source NVSS J224500−343030 is offset from the centre of the galaxy by 2.6 arcsec, which is significant when compared with the uncertainty due to the noise (≈ 26 mas) and calibration in NVSS (≈ 0.5 arcsec; Condon et al 1998), and the known astrometric error of the VLA with respect to optical surveys (≈ 20 mas; e.g.…”

Section: Cross-matching With Optically Identified Galaxiesmentioning

confidence: 99%

FLASH early science – discovery of an intervening H i 21-cm absorber from an ASKAP survey of the GAMA 23 field

Allison

Sadler

Bellstedt

et al. 2020

Monthly Notices of the Royal Astronomical Society

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We present early science results from the First Large Absorption Survey in H I (FLASH), a spectroscopically blind survey for 21-cm absorption lines in cold hydrogen (H I) gas at cosmological distances using the Australian Square Kilometre Array Pathfinder (ASKAP). We have searched for H I absorption towards 1253 radio sources in the GAMA 23 field, covering redshifts between z = 0.34 and 0.79 over a sky area of approximately 50 deg 2 . In a purely blind search we did not obtain any detections of 21-cm absorbers above our reliability threshold. Assuming a fiducial value for the H I spin temperature of T spin = 100 K and source covering fraction c f = 1, the total comoving absorption path length sensitive to all Damped Lyman α Absorbers (DLAs; N HI ≥ 2 × 10 20 cm −2 ) is ∆X = 6.6 ± 0.3 (∆z = 3.7 ± 0.2) and super-DLAs (N HI ≥ 2 × 10 21 cm −2 ) is ∆X = 111 ± 6 (∆z = 63 ± 3). We estimate upper limits on the H I column density frequency distribution function that are consistent with measurements from prior surveys for redshifted optical DLAs, and nearby 21-cm emission and absorption. By cross-matching our sample of radio sources with optical spectroscopic identifications of galaxies in the GAMA 23 field, we were able to detect 21-cm absorption at z = 0.3562 towards NVSS J224500−343030, with a column density of N HI = (1.2±0.1)×10 20 (T spin /100 K) cm −2 . The absorber is associated with GAMA J22450.05−343031.7, a massive early-type galaxy at an impact parameter of 17 kpc with respect to the radio source and which may contain a massive (M HI 3 × 10 9 M ) gas disc. Such gas-rich early types are rare, but have been detected in the nearby Universe.

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“…The reduced spectra extend redwards from approximately 3800 Å and therefore miss the [OII]λ3727 doublet. (Kuijken et al 2019); the galaxies are separated by a projected distance of 184 (30 kpc). The SALT-RSS longslit is shown in blue, and the SDSS fibers are indicated in green.…”

Section: Data From the Sloan Digital Sky Survey IIImentioning

confidence: 99%

“…Deeper observations, however, are required to determine the degree to which the tidal debris from VV 655 lacks stars. Figure 3 shows the g-band KiDS image of NGC 4418 (Kuijken et al 2019) with a model of the galaxy disk subtracted to display an arm-like feature on the southwest side of the galaxy. To construct the disk profile, we made a smooth model of the light distribution using the IRAF task ellipse.…”

Section: Imaging and Photometrymentioning

confidence: 99%

VV 655 and NGC 4418: Implications of an interaction for the evolution of a LIRG

Boettcher

Gallagher

Ohyama

et al. 2020

A&A

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Context. VV 655, a dwarf irregular galaxy with HI tidal debris, is a companion to the lenticular luminous infrared galaxy (LIRG) NGC 4418. NGC 4418 stands out among nearby LIRGs due to its dense central concentration of molecular gas and the dusty, bi-polar structures along its minor axis suggestive of a wind driven by a central starburst and possible nuclear activity. Aims. We seek to understand the consequences of the ongoing minor interaction between VV 655 and NGC 4418 for the evolution of the LIRG. Specifically, we consider the origin of the gas supply responsible for the unusual nuclear properties of NGC 4418. Methods. We investigate the structural, kinematic, and chemical properties of VV 655 and NGC 4418 by analyzing archival imaging data and optical spectroscopic observations from the SDSS-III and new spectra from SALT-RSS. We characterize their gas-phase metal abundances and spatially resolved, ionized gas kinematics to better understand whether gas transfer between VV 655 and NGC 4418 resulted in the highly obscured nucleus of the LIRG. Results. The gas-phase metallicity in NGC 4418 significantly exceeds that in VV 655. No kinematic disturbances in the ionized gas are observed along the minor axis of NGC 4418, but we see evidence for ionized gas outflows from VV 655 that may increase the cross-section for gas stripping in grazing collisions. A faint, asymmetric outer arm is detected in NGC 4418 of the type normally associated with galaxy-galaxy interactions. Conclusions. The simplest model suggests that the minor interaction between VV 655 and NGC 4418 produced the unusual nuclear properties of the LIRG via tidal torquing of the interstellar medium of NGC 4418 rather than through a significant gas transfer event. In addition to inducing a central concentration of gas in NGC 4418, this interaction also produced an enhanced star formation rate and an outer tidal arm in the LIRG. The VV 655-NGC 4418 system offers an example of the potential for minor collisions to alter the evolutionary pathways of giant galaxies.

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The fourth data release of the Kilo-Degree Survey: ugri imaging and nine-band optical-IR photometry over 1000 square degrees

Cited by 282 publications

References 69 publications

Tomographic galaxy clustering with the Subaru Hyper Suprime-Cam first year public data release

Tomographic galaxy clustering with the Subaru Hyper Suprime-Cam first year public data release

FLASH early science – discovery of an intervening H i 21-cm absorber from an ASKAP survey of the GAMA 23 field

VV 655 and NGC 4418: Implications of an interaction for the evolution of a LIRG

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