scholarly journals Properties of the environment around active galactic nucleus / luminous galaxy pairs through the HSC wide survey

2020 ◽  
Vol 72 (4) ◽  
Author(s):  
Yuji Shirasaki ◽  
Masayuki Akiyama ◽  
Yoshiki Toba ◽  
Wanqiu He ◽  
Tomotsugu Goto
Keyword(s):  
Active Galactic Nucleus ◽  
Absolute Magnitude ◽  
Large Mass ◽  
Dark Matter Halo ◽  
Photometric Redshift ◽  
Radio Detection ◽  
Blue Galaxies ◽  
Redshift Survey ◽  
Strategic Program ◽  
Blue Galaxy

Abstract We investigated the properties of active galactic nucleus (AGN) environments, particularly environments where the association of a luminous galaxy (LG) is found within 4 Mpc from an AGN with redshift 0.8–1.1. For comparison, three additional AGN environments, (namely, AGNs of all types, type 1 AGNs with X-ray and/or radio detection, and type 2 AGNs) and an environment of blue M*, the characteristic luminosity of the Schechter function, galaxies were investigated. The cross-correlation function with the surrounding galaxies was measured and compared between the AGN and blue galaxy samples. We also compared the distributions of color, absolute magnitude, and stellar mass of the galaxies around such target objects. The properties of clusters detected using surrounding galaxies selected based on a photometric redshift were examined and compared for different samples. The target AGNs were drawn from the Million Quasars (MILLIQUAS) catalog, and the blue galaxies were drawn from six redshift survey catalogs (SDSS, WiggleZ, DEEP2, VVDS, VIPERS, and PRIMUS). The galaxies used as a measure of the environment around the targets were drawn from the S18a internal data released by the Hyper Suprime-Cam Subaru Strategic Program. We found that, among the five AGN and blue galaxy samples considered, the environment of AGN–LG pairs is the most enriched with luminous galaxies. We also found an enhancement in the number of mass-selected clusters in the AGN–LG pair sample against those in the other samples. The results obtained in this study indicate that existence of multiple clusters is the major driver in the association of AGNs and LGs, rather than a single large-mass dark matter halo hosting the AGN.

scholarly journals Excess Clustering on Large Scales in the MegaZ DR7 Photometric Redshift Survey

2011 ◽  
Vol 106 (24) ◽  
Author(s):  
Shaun A. Thomas ◽  
Filipe B. Abdalla ◽  
Ofer Lahav
Keyword(s):  
Photometric Redshift ◽  
Redshift Survey

scholarly journals Measuring the local matter density usingGaiaDR2

2019 ◽  
Vol 623 ◽  
pp. A30 ◽  
Author(s):  
A. Widmark
Keyword(s):  
Density Distribution ◽  
Vertical Velocity ◽  
Galactic Plane ◽  
Absolute Magnitude ◽  
Matter Density ◽  
Dark Matter Halo ◽  
Constant Density ◽  
Bayesian Hierarchical ◽  
Error Covariance ◽  
Systematic Effects

Aims.We determine the total dynamical matter density in the solar neighbourhood using the secondGaiadata release (DR2).Methods.The dynamical matter density distribution is inferred in a framework of a Bayesian hierarchical model, which accounts for position and velocity of all individual stars, as well as the full error covariance matrix of astrometric observables, in a joint fit of the vertical velocity distribution and stellar number density distribution. This was done for eight separate data samples, with different cuts in observed absolute magnitude, each containing about 25 000 stars. The model for the total matter density does not rely on any underlying baryonic model, although we assumed that it is symmetrical, smooth, and monotonically decreasing with distance from the mid-plane.Results.We infer a density distribution which is strongly peaked in the region close to the Galactic plane (≲60 pc), for all eight stellar samples. Assuming a baryonic model and a dark matter halo of constant density, this corresponds to a surplus surface density of approximately 5–9M⊙pc−2. For the Sun’s position and vertical velocity with respect to the Galactic plane, we inferZ⊙ = 4.76 ± 2.27 pc andW⊙ = 7.24 ± 0.19 km s−1.Conclusions.These results suggest a surplus of matter close to the Galactic plane, possibly explained by an underestimated density of cold gas. We discuss possible systematic effects that could bias our result, for example unmodelled non-equilibrium effects, and how to account for such effects in future extensions of this work.

scholarly journals Low Surface Brightness Galaxies and the Field Galaxy Luminosity Function

1996 ◽  
Vol 171 ◽  
pp. 446-446 ◽  
Author(s):  
D. Sprayberry ◽  
C. D. Impey ◽  
G. D. Bothun ◽  
M. J. Irwin
Keyword(s):  
Surface Brightness ◽  
Luminosity Function ◽  
Substantial Fraction ◽  
Low Surface Brightness ◽  
Blue Galaxies ◽  
Best Fitting ◽  
Redshift Survey ◽  
Low Surface Brightness Galaxies ◽  
Galaxy Luminosity Function ◽  
Field Galaxy

We have developed a catalog of local low surface brightness galaxies (LSBGs) which is selected by objective criteria. We present here a luminosity function (LF) for LSBGs based on that catalog. This LF includes the effects of the completeness corrections to the LSBG catalog, and includes only galaxies with surface brightnesses (22.25 ≤ μB(0) ≤ 24.5) fainter than those included in the CfA Redshift Survey (see Marzke et al. 1994, AJ 108, 437). The best-fitting Schechter function has parameters α = –1.42, M∗B = −18.34, and Φ∗ = 0.0036 h3 Mpc–3 mag–1. Thus, surveys which do not take account of the observational selection bias imposed by surface brightness are missing a substantial fraction of the local galaxies, but, this missed fraction is not large enough to explain the counts of faint blue galaxies observed at moderate redshift.

scholarly journals Getting leverage on inflation with a large photometric redshift survey

2015 ◽  
Vol 2015 (06) ◽  
pp. 042-042 ◽  
Author(s):  
Tobias Basse ◽  
Jan Hamann ◽  
Steen Hannestad ◽  
Yvonne Y.Y. Wong
Keyword(s):  
Photometric Redshift ◽  
Redshift Survey

scholarly journals Weak-lensing clusters from HSC survey first-year data: Mitigating the dilution effect of foreground and cluster-member galaxies

2020 ◽  
Vol 72 (5) ◽  
Author(s):  
Takashi Hamana ◽  
Masato Shirasaki ◽  
Yen-Ting Lin
Keyword(s):  
Dilution Effect ◽  
Weak Lensing ◽  
First Year ◽  
Cluster Member ◽  
The Public ◽  
Photometric Redshift ◽  
Source Sample ◽  
Strategic Program ◽  
Dilution Effects ◽  
Cross Match

Abstract We present a weak-lensing cluster search using Hyper Suprime-Cam Subaru Strategic Program (HSC survey) first-year data. We pay special attention to the dilution effect of cluster-member and foreground galaxies on weak-lensing signals from clusters of galaxies; we adopt the globally normalized weak-lensing estimator which is least affected by cluster-member galaxies, and we select source galaxies by using photometric redshift information to mitigate the effect of foreground galaxies. We produce six samples of source galaxies with different low-z galaxy cuts, construct weak-lensing mass maps for each source sample, and search for high peaks in the mass maps that cover an effective survey area of ∼120 deg2. We combine six catalogs of high peaks into a sample of cluster candidates which contains 124 high peaks with signal-to-noise ratios greater than five. We cross-match the peak sample with the public optical cluster catalog constructed from the same HSC survey data to identify cluster counterparts of the peaks. We find that 107 out of 124 peaks have matched clusters within 5′ of peak positions. Among them, we define a subsample of 64 secure clusters that we use to examine dilution effects on our weak-lensing cluster search. We find that source samples with low-z galaxy cuts mitigate the dilution effect on weak-lensing signals of high-z clusters ($z \gtrsim 0.3$), and thus combining multiple peak catalogs from different source samples improves the efficiency of weak-lensing cluster searches.

scholarly journals Testing Gravity using Void Profiles

2014 ◽  
Vol 11 (S308) ◽  
pp. 555-560 ◽  
Author(s):  
Yan-Chuan Cai ◽  
Nelson Padilla ◽  
Baojiu Li
Keyword(s):  
Dark Matter ◽  
Gravitational Lensing ◽  
Modified Gravity ◽  
Large Scale ◽  
Line Of Sight ◽  
Number Density ◽  
Density Profiles ◽  
Photometric Redshift ◽  
Redshift Survey ◽  
Near Future

AbstractWe investigate void properties inf(R)models using N-body simulations, focusing on their differences from General Relativity (GR) and their detectability. In the Hu-Sawickif(R)modified gravity (MG) models, the halo number density profiles of voids are not distinguishable from GR. In contrast, the samef(R)voids are more empty of dark matter, and their profiles are steeper. This can in principle be observed by weak gravitational lensing of voids, for which the combination of a spectroscopic redshift and a lensing photometric redshift survey over the same sky is required. Neglecting the lensing shape noise, thef(R)model parameter amplitudesfR0=10-5and 10-4may be distinguished from GR using the lensing tangential shear signal around voids by 4 and 8 σ for a volume of 1 (Gpc/h)3. The line-of-sight projection of large-scale structure is the main systematics that limits the significance of this signal for the near future wide angle and deep lensing surveys. For this reason, it is challenging to distinguishfR0=10-6from GR. We expect that this can be overcome with larger volume. The halo void abundance being smaller and the steepening of dark matter void profiles inf(R)models are unique features that can be combined to break the degeneracy betweenfR0and σ8.

scholarly journals Deep ugrizY imaging and DEEP2/3 spectroscopy: a photometric redshift testbed for LSST and public release of data from the DEEP3 Galaxy Redshift Survey

2019 ◽  
Vol 488 (4) ◽  
pp. 4565-4584 ◽  
Author(s):  
Rongpu Zhou ◽  
Michael C Cooper ◽  
Jeffrey A Newman ◽  
Matthew L N Ashby ◽  
James Aird ◽  
...  
Keyword(s):  
Object Size ◽  
Random Forest Regression ◽  
Photometric Redshifts ◽  
Size Information ◽  
Photometric Redshift ◽  
Point Spread ◽  
Spread Function ◽  
Redshift Survey ◽  
Galaxy Redshift ◽  
Empirical Tests

ABSTRACT We present catalogues of calibrated photometry and spectroscopic redshifts in the Extended Groth Strip, intended for studies of photometric redshifts (photo-z’s). The data includes ugriz photometry from Canada–France–Hawaii Telescope Legacy Survey (CFHTLS) and Y-band photometry from the Subaru Suprime camera, as well as spectroscopic redshifts from the DEEP2, DEEP3, and 3D-HST surveys. These catalogues incorporate corrections to produce effectively matched-aperture photometry across all bands, based upon object size information available in the catalogue and Moffat profile point spread function fits. We test this catalogue with a simple machine learning-based photometric redshift algorithm based upon Random Forest regression, and find that the corrected aperture photometry leads to significant improvement in photo-z accuracy compared to the original SExtractor catalogues from CFHTLS and Subaru. The deep ugrizY photometry and spectroscopic redshifts are well suited for empirical tests of photometric redshift algorithms for LSST. The resulting catalogues are publicly available at http://d-scholarship.pitt.edu/36064/. We include a basic summary of the strategy of the DEEP3 Galaxy Redshift Survey to accompany the recent public release of DEEP3 data.

scholarly journals The 2dF Galaxy Redshift Survey: the blue galaxy fraction and implications for the Butcher-Oemler effect

2004 ◽  
Vol 351 (1) ◽  
pp. 125-132 ◽  
Author(s):  
Roberto De Propris ◽  
Matthew Colless ◽  
John A. Peacock ◽  
Warrick J. Couch ◽  
Simon P. Driver ◽  
...  
Keyword(s):  
Redshift Survey ◽  
Galaxy Redshift ◽  
Blue Galaxy

scholarly journals The Las Campanas Infrared Survey. IV. The Photometric Redshift Survey and the Rest‐FrameR‐Band Galaxy Luminosity Function at 0.5 ≤ z ≤ 1.5

2003 ◽  
Vol 586 (2) ◽  
pp. 745-764 ◽  
Author(s):  
Hsiao‐Wen Chen ◽  
Ronald O. Marzke ◽  
Patrick J. McCarthy ◽  
P. Martini ◽  
R. G. Carlberg ◽  
...  
Keyword(s):  
Luminosity Function ◽  
Photometric Redshift ◽  
Redshift Survey ◽  
Galaxy Luminosity Function ◽  
Infrared Survey

scholarly journals The VIMOS Public Extragalactic Redshift Survey (VIPERS)

2018 ◽  
Vol 620 ◽  
pp. A193 ◽  
Author(s):  
D. Vergani ◽  
B. Garilli ◽  
M. Polletta ◽  
P. Franzetti ◽  
M. Scodeggio ◽  
...  
Keyword(s):  
Star Formation ◽  
Emission Line ◽  
Starburst Galaxies ◽  
Host Galaxies ◽  
Star Formation Activity ◽  
Blue Galaxies ◽  
Redshift Survey ◽  
The Rich ◽  
Stellar Masses ◽  
Red Sequence

Aims. We analyse the properties of the host galaxies of a [NeV]-selected sample to investigate whether and how they are affected by the AGN. Methods. We have selected a sample of galaxies at 0.62 <  z <  1.2 from the VIMOS Public Extragalactic Redshift Survey (VIPERS) and divided it in blue cloud galaxies, red passive galaxies and green valley galaxies using the NUVrK diagram. Within each category, galaxies with AGN activity were identified based on the detection of the high-ionisation [NeV]λ3426 emission line. For each galaxy we derived several properties (stellar age and mass, the (r−K) colour, the [OII] luminosity) and compared them between active and inactive galaxies matched in stellar mass and redshift. Results. We find statistically significant differences in the properties between active and inactive galaxies. These differences imply that the AGN is more often found in galaxies with younger stellar populations and more recent star-forming activity than their parent samples. Interestingly, the AGN identified through the [NeV]λ3426 emission line is not commonly found by traditional AGN-selection techniques based on shallow X-ray data, mid-IR colours, and classical line diagnostic diagrams, and might thus reveal a specific evolutionary phase. The spectral analysis reveals a sub-set of AGN within the blue cloud that has spectral signatures implying a sudden suppression of star formation activity similar to post-starburst galaxies. Conclusion. Using the rich dataset of the large VIPERS sample we identify a novel class of active post-starburst galaxies that would be missed by traditional selection techniques. These galaxies belong to the blue cloud, but their star-formation activity has been recently suppressed, possibly by the AGN identified through the presence of the [NeV]λ3426 emission line in their spectra. Our results support the idea that AGN feedback may be responsible for halting star-formation in active blue galaxies and for their transition into the red sequence, at least in the 0.6–1.2 redshift range and for stellar masses greater than 5 × 1010 ℳ⊙. Our results are based on a complete spectroscopic sample and limited by the [NeV] observability, and the AGN can be variable and with a relatively short duty cycle. Considering this, AGN feedback that makes blue galaxies quickly transition to the red sequence may be even more common than previously believed.

Sign in / Sign up

Export Citation Format

Share Document