2MASS Redshift Survey Research Articles

Velocity–density correlations from the cosmicflows-3 distance catalogue and the 2MASS Redshift Survey

The peculiar velocity of a mass tracer is on average aligned with the dipole modulation of the surrounding mass density field. We present a first measurement of the correlation between radial peculiar velocities of objects in the cosmicflows-3 catalog and the dipole moment of the 2MRS galaxy distribution in concentric spherical shells centered on these objects. Limiting the analysis to cosmicflows-3 objects with distances of $100 \rm Mpc h^{-1}$, the correlation function is detected at a confidence level $> 4\sigma$. The measurement is found consistent with the standard $\Lambda$CDM model at $< 1.7\sigma$ level. We formally derive the constraints $0.32<\Omega^{0.55}\sigma_8<0.48$ ($68\% $ confidence level) or equivalently $0.34<\Omega^{0.55}/b<0.52$, where $b$ is the galaxy bias factor. Deeper and improved peculiar velocity catalogs will substantially reduce the uncertainties, allowing tighter constraints from this type of correlations.

Can anisotropy in the galaxy distribution tell the bias?

We use information entropy to analyze the anisotropy in the mock galaxy catalogues from dark matter distribution and simulated biased galaxy distributions from $\Lambda$CDM N-body simulation. We show that one can recover the linear bias parameter of the simulated galaxy distributions by comparing the radial, polar and azimuthal anisotropies in the simulated galaxy distributions with that from the dark matter distribution. This method for determination of the linear bias requires only $O(N)$ operations as compared to $O(N^{2})$ or at least $O(N \log N)$ operations required for the methods based on the two-point correlation function and the power spectrum. We apply this method to determine the linear bias parameter for the galaxies in the 2MASS Redshift Survey (2MRS) and find that the 2MRS galaxies in the $K_{s}$ band have a linear bias of $\sim 1.3$.

Detection prospects for high energy neutrino sources from the anisotropic matter distribution in the local Universe

Constraints on the number and luminosity of the sources of the cosmic neutrinos detected by IceCube have been set by targeted searches for point sources. We set complementary constraints by using the 2MASS Redshift Survey (2MRS) catalogue, which maps the matter distribution of the local Universe. Assuming that the distribution of the neutrino sources follows that of matter, we look for correlations between ``warm'' spots on the IceCube skymap and the 2MRS matter distribution. Through Monte Carlo simulations of the expected number of neutrino multiplets and careful modelling of the detector performance (including that of IceCube-Gen2), we demonstrate that sources with local density exceeding 10−6 Mpc−3 and neutrino luminosity Lν ≲ 1042 erg s−1 (1041 erg s−1) will be efficiently revealed by our method using IceCube (IceCube-Gen2). At low luminosities such as will be probed by IceCube-Gen2, the sensitivity of this analysis is superior to requiring statistically significant direct observation of a point source.

GALAXY GROUPS IN THE 2MASS REDSHIFT SURVEY

ABSTRACT A galaxy group catalog is constructed from the 2MASS Redshift Survey (2MRS) with the use of a halo-based group finder. The halo mass associated with a group is estimated using a “GAP” method based on the luminosity of the central galaxy and its gap with other member galaxies. Tests using mock samples show that this method is reliable, particularly for poor systems containing only a few members. On average, 80% of all the groups have completeness , and about 65% of the groups have zero contamination. Halo masses are estimated with a typical uncertainty of . The application of the group finder to the 2MRS gives 29,904 groups from a total of 43,246 galaxies at , with 5286 groups having two or more members. Some basic properties of this group catalog is presented, and comparisons are made with other group catalogs in overlap regions. With a depth to and uniformly covering about 91% of the whole sky, this group catalog provides a useful database to study galaxies in the local cosmic web, and to reconstruct the mass distribution in the local universe.

Fast radio bursts counterparts in the scenario of supergiant pulses

Abstract We discuss identification of possible counterparts and persistent sources related to fast radio bursts (FRBs) in the framework of the model of supergiant pulses from young neutron stars with large spin-down luminosities. In particular, we demonstrate that at least some of the sources of FRBs can be observed as ultraluminous X-ray sources (ULXs). At the moment no ULXs are known to be coincident with localization areas of FRBs. We searched for a correlation of FRB positions with galaxies in the 2MASS Redshift survey catalogue. Our analysis produced statistically insignificant overabundance (p-value ≈ 4 per cent) of galaxies in error boxes of FRBs. In the very near future with even modestly increased statistics of FRBs and with the help of dedicated X-ray observations and all-sky X-ray surveys it will be possible to decisively prove or falsify the supergiant pulses model.

A Bayesian analysis of the 69 highest energy cosmic rays detected by the Pierre Auger Observatory

The origins of ultra-high energy cosmic rays (UHECRs) remain an open question. Several attempts have been made to cross-correlate the arrival directions of the UHECRs with catalogs of potential sources, but no definite conclusion has been reached. We report a Bayesian analysis of the 69 events from the Pierre Auger Observatory (PAO), that aims to determine the fraction of the UHECRs that originate from known AGNs in the Veron-Cety & Veron (VCV) catalog, as well as AGNs detected with the Swift Burst Alert Telescope (Swift-BAT), galaxies from the 2MASS Redshift Survey (2MRS), and an additional volume-limited sample of 17 nearby AGNs. The study makes use of a multi-level Bayesian model of UHECR injection, propagation and detection. We find that for reasonable ranges of prior parameters, the Bayes factors disfavour a purely isotropic model. For fiducial values of the model parameters, we report 68% credible intervals for the fraction of source originating UHECRs of 0.09+0.05-0.04, 0.25+0.09-0.08, 0.24+0.12-0.10, and 0.08+0.04-0.03 for the VCV, Swift-BAT and 2MRS catalogs, and the sample of 17 AGNs, respectively.

The WSRT ZoA Perseus-Pisces filament wide-field H i imaging survey – I. H i catalogue and atlas

We present results of a blind 21cm HI-line imaging survey of a galaxy overdensity located behind the Milky Way at $\ell,b$ $\approx$ 160 deg, 0.5 deg. The overdensity corresponds to a Zone-of-Avoidance crossing of the Perseus-Pisces Supercluster filament. Although it is known that this filament contains an X-ray galaxy cluster (3C129) hosting two strong radio galaxies, little is known about galaxies associated with this potentially rich cluster because of the high Galactic dust extinction. We mapped a sky area of $\sim$9.6 sq.deg using the Westerbork Synthesis Radio Telescope in a hexagonal mosaic of 35 pointings observed for 12 hours each, in the radial velocity range $cz = 2400 - 16600$ km/s. The survey has a sensitivity of 0.36 mJy/beam rms at a velocity resolution of 16.5 km/s. We detected 211 galaxies, 62% of which have a near-infrared counterpart in the UKIDSS Galactic Plane Survey. We present a catalogue of the HI properties and an HI atlas containing total intensity maps, position-velocity diagrams, global HI profiles and UKIDSS counterpart images. For the resolved galaxies we also present HI velocity fields and radial HI surface density profiles. A brief analysis of the structures outlined by these galaxies finds that 87 of them lie at the distance of the Perseus-Pisces Supercluster ($cz \sim 4000 - 8000$ km/s) and seem to form part of the 3C129 cluster. Further 72 detections trace an overdensity at a velocity of $cz \approx$ 10000 km/s and seem to coincide with a structure predicted from mass density reconstructions in the first 2MASS Redshift Survey.

2MTF – V. Cosmography, β, and the residual bulk flow

Using the Tully-Fisher relation, we derive peculiar velocities for the 2MASS Tully-Fisher Survey and describe the velocity field of the nearby Universe. We use adaptive kernel smoothing to map the velocity field, and compare it to reconstructions based on the redshift space galaxy distributions of the 2MASS Redshift Survey (2MRS) and the IRAS Point Source Catalog Redshift Survey (PSCz). With a standard $\chi^2$ minimization fit to the models, we find that the PSCz model provides a better fit to the 2MTF velocity field data than does the 2MRS model, and provides a value of $\beta$ in greater agreement with literature values. However, when we subtract away the monopole deviation in the velocity zeropoint between data and model, the 2MRS model also produces a value of $\beta$ in agreement with literature values. We also calculate the `residual bulk flow': the component of the bulk flow not accounted for by the models. This is $\sim 250$ km/s when performing the standard fit, but drops to $\sim 150$ km/s for both models when the aforementioned monopole offset between data and models is removed. This smaller number is more in line with theoretical expectations, and suggests that the models largely account for the major structures in the nearby Universe responsible for the bulk velocity.

GALAXY GROUPS: A 2MASS CATALOG

A galaxy group catalog is built from the sample of the 2MASS Redshift Survey almost complete to Ks=11.75 over 91% of the sky. Constraints in the construction of the groups were provided by scaling relations determined by close examination of well defined groups with masses between 10^11 and 10^15 Msun. Group masses inferred from Ks luminosities are statistically in agreement with masses calculated from application of the virial theorem. While groups have been identified over the full redshift range of the sample, the properties of the nearest and farthest groups are uncertain and subsequent analysis has only considered groups with velocities between 3,000 and 10,000 km/s. The 24,044 galaxies in this range are identified with 13,607 entities, 3,461 of them with two or more members. A group mass function is constructed. The Sheth-Tormen formalism provides a good fit to the shape of the mass function for group masses above 6/h x 10^12 Msun but the count normalization is poor. Summing all the mass associated with the galaxy groups between 3,000 and 10,000 km/s gives a density of collapsed matter as a fraction of the critical density of Omega_collapsed = 0.16.

Revisiting Olbers's paradox in a cellular universe

Olbers’s paradox puts some constraints on the current cosmologies, i.e., the sky is not innitely bright. A way to solve the paradox is to distinguish between the number and the density of the galaxies. A careful analysis has been made of the number of galaxies as a function of distance using the 2MASS Redshift Survey (2MRS) catalog. The obtained results for the nite intensity of light are compared with the intensity of the extra-galactic background at 520 nm.

The 6dF Galaxy Survey: peculiar velocity field and cosmography

We derive peculiar velocities for the 6dF Galaxy Survey (6dFGS) and describe the velocity field of the nearby ($z<0.055$) southern hemisphere. The survey comprises 8885 galaxies for which we have previously reported Fundamental Plane data. We obtain peculiar velocity probability distributions for the redshift space positions of each of these galaxies using a Bayesian approach. Accounting for selection bias, we find that the logarithmic distance uncertainty is 0.11 dex, corresponding to $26\%$ in linear distance. We use adaptive kernel smoothing to map the observed 6dFGS velocity field out to $cz \sim 16,000$ \kms, and compare this to the predicted velocity fields from the PSCz Survey and the 2MASS Redshift Survey. We find a better fit to the PSCz prediction, although the reduced $\chi^2$ for the whole sample is approximately unity for both comparisons. This means that, within the observational uncertainties due to redshift independent distance errors, observed galaxy velocities and those predicted by the linear approximation from the density field agree. However, we find peculiar velocities that are systematically more positive than model predictions in the direction of the Shapley and Vela superclusters, and systematically more negative than model predictions in the direction of the Pisces-Cetus Supercluster, suggesting contributions from volumes not covered by the models.

2MTF III. H i 21 cm observations of 1194 spiral galaxies with the Green Bank Telescope

We present HI 21cm observations of 1194 galaxies out to a redshift of 10,000 km/s selected as inclined spirals (i>60deg) from the 2MASS Redshift Survey. These observations were carried out at the National Radio Astronomy Observatory Robert C. Byrd Green Bank Telescope (GBT). This observing program is part of the 2MASS Tully-Fisher (2MTF) survey. This project will combine HI widths from these GBT observations with those from further dedicated observing at the Parkes Telescope, from the ALFALFA survey at Arecibo, and S/N>10 and spectral resolution, v_res < 10km/s published widths from a variety of telescopes. We will use these HI widths along with 2MASS photometry to estimate Tully-Fisher distances to nearby spirals and investigate the peculiar velocity field of the local Universe. In this paper we report on detections of neutral hydrogen in emission in 727 galaxies, and measure good signal-to-noise and symmetric HI global profiles suitable for use in the Tully-Fisher relation in 484.

The Revised IRAS-FSC Redshift Catalogue (RIFSCz)

We present a Revised IRAS-FSC Redshift Catalogue (RIFSCz) of 60,303 galaxies selected at 60 microns from the IRAS Faint Source Catalogue (FSC). This revision merges in data from the WISE All-Sky Data Release, the Tenth SDSS Data Release (DR10), the GALEX All-Sky Survey Source Catalog (GASC), the 2MASS Redshift Survey (2MRS) and the Planck Catalogue of Compact Sources (PCCS). The RIFSCz consists of accurate position, ultra-violet (UV), optical, near-, mid- and far-infrared, sub-millimetre (sub-mm) and/or radio identifications, spectroscopic redshift (if available) or photometric redshift (if possible), predicted far-infrared and sub-mm fluxes ranging from 12 to 1380 microns based upon the best-fit infrared template. We also provide stellar masses, star-formation rates and dust masses derived from the optical and infrared template fits, where possible. 56 of the galaxies in the RIFSCz have spectroscopic redshifts and a further 26 have photometric redshifts obtained through the template-fitting method. At S60 > 0.36 Jy, the 90% completeness limit of the FSC, 93 of the sources in the RIFSCz have either spectroscopic or photometric redshifts. An interesting subset of the catalogue is the sources detected by Planck at sub-mm wavelengths. 1200 sources have a detection at better than 5 sigma in at least one Planck band and a further 1186 sources have detections at 3-5 sigma in at least one Planck band.

What size haloes do local LIRGs live in?

This work investigates the preferred environment of local Luminous IR Galaxies (LIRGs) in terms of the host halos that they inhabit, and in comparison to a control galaxy sample. The LIRGs are drawn from the IRAS Point Source Catalogue redshift survey (PSCz), while the control sample is drawn from the 2MASS redshift survey (2MRS). A friends-of-friends algorithm was run on the 2MRS sample to identify galaxies living in the same dark matter halos and the PSCz galaxies were then associated with these identified halos. We show that the relative probability of finding local LIRGs with respect to 2MASS galaxies is largest in approximately group size halos (Mhalo~10^13M_sun), and declines both in the cluster regime and in smaller halos. This confirms, using a different technique than in previous work, that local LIRGs are indeed more abundant in group environments than elsewhere. We also find a trend between the LIR values of LIRGs and their location within their host dark matter halos, such that the average location of LIRGs with high IR luminosity is closer to the halo centre than for low IR luminosity galaxies. Moreover, this trend does not seem to depend on halo mass.

Anisotropy in the Hubble constant as modeled by density gradients

The all-sky maps of the observed variation of the Hubble constant can be reproduced from a theoretical point of view by introducing an intergalactic plasma with a variable number density of electrons. The observed averaged value and variance of the Hubble constant are reproduced by adopting a rim model, an auto-gravitating model, and a Voronoi diagrams model as the backbone for an auto-gravitating medium. We also analyze an astronomer's model based on the 3D spatial distribution of galaxies as given by the 2MASS Redshift Survey and an auto-gravitating Lane--Emden ($n=5$) profile of the electrons. The simulation which involves the Voronoi diagrams is done in a cubic box with sides of 100 Mpc. The simulation which involves the 2MASS covers the range of redshift smaller than 0.05.

The 2massTully–Fisher Survey: Mapping the mass in the Universe

AbstractThe 2mass Tully–Fisher Survey (2mtf) aims to measure Tully–Fisher (TF) distances for all bright, inclined spirals in the 2mass Redshift Survey (2mrs) using high-quality Hi widths and 2mass photometry. Compared with previous peculiar-velocity surveys, the 2mtf survey provides more accurate width measurements and more uniform sky coverage, combining observations with the Green Bank, Arecibo, and Parkes telescopes. With this new redshift-independent distance database, we will significantly improve our understanding of the mass distribution in the local Universe.

The linear velocity field of 2MASS Redshift Survey, Ks= 11.75 galaxies: constraints on β and bulk flow from the luminosity function

Using the nearly full sky Ks=11.75 2MASS Redshift Survey [2MRS]of ~45,000 galaxies we reconstruct the underlying peculiar velocity field and constrain the cosmological bulk flow within ~100. These results are obtained by maximizing the probability to estimate the absolute magnitude of a galaxy given its observed apparent magnitude and redshift. At a depth of ~60 Mpc/h we find a bulk flow Vb=(90\pm65,-230\pm65,50\pm65) km/s in agreement with the theoretical predictions of the LCDM model. The reconstructed peculiar velocity field that maximizes the likelihood is characterized by the parameter beta=0.323 +/- 0.08. Both results are in agreement with those obtained previously using the ~23,000 galaxies of the shallower Ks=11.25 2MRS survey. In our analysis we find that the luminosity function of 2MRS galaxies is poorly fitted by the Schechter form and that luminosity evolves such that objects become fainter with increasing redshift according to L(z)=L(z=0)(1+z)^(+2.7 +/-0.15).

THE 2MASS REDSHIFT SURVEY—DESCRIPTION AND DATA RELEASE

We present the results of the 2MASS Redshift Survey (2MRS), a ten-year project to map the full three-dimensional distribution of galaxies in the nearby Universe. The 2 Micron All-Sky Survey (2MASS) was completed in 2003 and its final data products, including an extended source catalog (XSC), are available on-line. The 2MASS XSC contains nearly a million galaxies with Ks <= 13.5 mag and is essentially complete and mostly unaffected by interstellar extinction and stellar confusion down to a galactic latitude of |b|=5 deg for bright galaxies. Near-infrared wavelengths are sensitive to the old stellar populations that dominate galaxy masses, making 2MASS an excellent starting point to study the distribution of matter in the nearby Universe. We selected a sample of 44,599 2MASS galaxies with Ks <= 11.75 mag and |b|>=5 deg (>= 8 deg towards the Galactic bulge) as the input catalog for our survey. We obtained spectroscopic observations for 11,000 galaxies and used previously-obtained velocities for the remainder of the sample to generate a redshift catalog that is 97.6% complete to well-defined limits and covers 91% of the sky. This provides an unprecedented census of galaxy (baryonic mass) concentrations within 300 Mpc. Earlier versions of our survey have been used in a number of publications that have studied the bulk motion of the Local Group, mapped the density and peculiar velocity fields out to 50 Mpc, detected galaxy groups, and estimated the values of several cosmological parameters. Additionally, we present morphological types for a nearly-complete sub-sample of 20,860 galaxies with Ks < 11.25 mag and |b|>= 10 deg.

The intergalactic Newtonian gravitational field and the shell theorem

The release of the 2MASS Redshift Survey (2MRS) with its 44599 galaxies allows the deduction of their masses in nearly complete sample. A cubic box with side of 37 Mpc containing 2429 galaxies is extracted and the Newtonian gravitational field is evaluated both at the center of the box as well as in 101 x 101 x 101 grid points of the box. The obtained results are then discussed in the light of the shell theorem which states that inside of a sphere the gravitational field is zero.

IS THE TWO MICRON ALL SKY SURVEY CLUSTERING DIPOLE CONVERGENT?

There is a long-standing controversy about the convergence of the dipole moment of the galaxy angular distribution (the so-called clustering dipole). We study the growth of the clustering dipole of galaxies as a function of the limiting flux of the sample from the Two Micron All Sky Survey (2MASS). Contrary to some earlier claims, we find that the dipole does not converge before the completeness limit of the 2MASS Extended Source Catalog, i.e. up to 13.5 mag in the near-infrared K_s band (equivalent to an effective distance of 300 Mpc/h). We compare the observed growth of the dipole with the theoretically expected, conditional one (i.e., given the velocity of the Local Group relative to the CMB), for the LambdaCDM power spectrum and cosmological parameters constrained by WMAP. The observed growth turns out to be within 1-sigma confidence level of its theoretical counterpart once the proper observational window of the 2MASS flux-limited catalog is included. For a contrast, if the adopted window is a top-hat, then the predicted dipole grows significantly faster and converges to its final value for a distance of about 300 Mpc/h. By comparing the observational windows, we show that for a given flux limit and a corresponding distance limit, the 2MASS flux-weighted window passes less large-scale signal than the top-hat one. We conclude that the growth of the 2MASS dipole for effective distances greater than 200 Mpc/h is only apparent. On the other hand, for a distance of 80 Mpc/h (mean depth of the 2MASS Redshift Survey) and the LambdaCDM power spectrum, the true dipole is expected to reach only ~80% of its final value. Eventually, since for the window function of 2MASS the predicted growth is consistent with the observed one, we can compare the two to evaluate beta = (Omega_m)^0.55 / b. The result is beta = 0.38+-0.04, which leads to an estimate of the density parameter Omega_m = 0.20+-0.08.