Galaxy Groups Within 3500 km s⁻¹

Abstract

A study of the group properties of galaxies in our immediate neighborhood provides a singular opportunity to observationally constrain the halo mass function, a fundamental characterization of galaxy formation. Detailed studies of individual groups have provided the coefficients of scaling relations between a proxy for the virial radius, velocity dispersion, and mass that usefully allows groups to be defined over the range 10 10 −10 15 M ⊙ . At a second hierarchical level, associations are defined as regions around collapsed halos extending to the zero velocity surface at the decoupling from cosmic expansion. The most remarkable result of the study emerges from the construction of the halo mass function from the sample. At ∼ 10 12 M ⊙ there is a jog from the expectation Sheth-Tormen function, such that halo counts drop by a factor ∼ 3 in all lower mass bins.

The Sheet of Giants: Unusual properties of the Milky Way’s immediate neighbourhood

“…The concentration of bright galaxies in the Local Volume is also apparent or noted in the results of several recent studies (Karachentsev & Kudrya 2014;Klypin et al 2015;Kourkchi & Tully 2017). As Fig.…”

“…The Local Volume contains a large number of bright and massive galaxies (McCall 2014;Karachentsev & Kudrya 2014;Klypin et al 2015;Kourkchi & Tully 2017). The ring-like concentration of bright galaxies at distances of ≈ 3 − 5 Mpc around the Local Group was dubbed 'The Council of Giants' by McCall (2014).…”

Structure and kinematics of the Virgo cluster of galaxies

“…Thus, Sandage et al (1985) derived the total blue luminosity of the Virgo galaxies within 6 • core to be 1.4 × 10 12 L at the distance of 16.5 Mpc. According to Kourkchi and Tully (2017), the galaxies in the whole Virgo association have an integrated K-band luminosity of 1 × 10 13 L , with 5 × 10 12 L in the collapsed core.…”

How Many Kilonovae Can Be Found in Past, Present, and Future Survey Data Sets?

“…The counterpart was identified as a point source located near NGC 4993. This galaxy is 40 Mpc away, with redshift = z 0.0098 (Kourkchi & Tully 2017). In a companion paper by Soares-Santos et al 2017, we use our DECam (Flaugher et al 2015) search data to show the likelihood that the transient is in fact directly connected to the GW event is >99%.…”