Study of galaxies in the Lynx-Cancer void

Abstract

Context. Void population consists mainly of late-type and low surface brightness (LSB) dwarf galaxies whose atomic hydrogen is the main component of their baryonic matter. Therefore, observations of void galaxy Hi are mandatory in order to understand their evolution and dynamics. Aims. Our aim was to obtain integrated Hi parameters for a fainter part of the nearby Lynx-Cancer void galaxy sample (total of 45 objects) with the Nançay Radio Telescope (NRT) and to conduct the comparative analysis of all the 103 void galaxies with known Hi data with a sample of similar galaxies residing in denser environments of the Local Volume. Methods. For Hi observations we used the NRT with its sensitive antenna/receiver system FORT and standard processing. The comparison of the void and control samples on the parameter M(HI)/L B is conducted with the non-parametric method , "The 2×2 Contingency Table test". Results. We obtained new Hi data for about 40 % of the Lynx-Cancer galaxy sample. Along with data from the literature, we use these new data for further analysis of 103 void objects. The proxy of the evolutional parameter M(HI)/L B of the void sample is compared with that of 82 galaxies of morphological types 8-10 residing in the Local Volume (LV) groups and aggregates. Conclusions. At the confidence level of P = 0.988, we conclude that for the same luminosity, these void galaxies are systematically gas-richer, on average by ∼39%. This result is consistent with the authors' earlier conclusion on the smaller gas metallicities and evidence for the slower low-mass galaxy evolution in voids.

Study of galaxies in the Eridanus void. Sample and oxygen abundances

“…The recent Giant Meterwave Radio Telescope (GMRT) Hi mapping of a subsample of this void galaxies revealed three extremely gas-rich blue unevolved dwarfs (Chengalur & Pustilnik 2013;Chengalur, Pustilnik, Egorova 2017). The analysis and statistical study of photometric parameters (Perepelitsyna, Pustilnik, & Kniazev 2014) and of integrated Hi data (Pustilnik & Martin 2016), as well as of the significantly extended data on metallicities of this void galaxies ) allows one to conclude that void galaxies evolve slower then their analogs in denser environments.…”

Void galaxies in the nearby Universe – I. Sample description

“…There are direct observational indications on the enhanced gas mass fraction in void galaxies. But, on the one hand, they are not numerous due to small statistics for nearby voids (Pustilnik & Martin 2016). On the other hand, for more luminous galaxies in more distant voids (e.g., VGS, Kreckel et al (2011Kreckel et al ( , 2012), the situation with the gas mass fraction with respect of the control ALFALFA sample is less certain despite a substantial number of found the lower luminosity gas-rich objects.…”

“…In the recent series of papers we suggested a complementary approach aimed to study galaxy properties in a nearby Lynx-Cancer void, with the emphasis on the least massive void representatives Pustilnik, Tepliakova & Kniazev 2011a;Pustilnik et al 2011b;Perepelitsyna et al 2014;Pustilnik & Martin 2016;Pustilnik et al , 2005. These studies resulted in the firm conclusions on a systematically lower metallicity of gas and a higher H i-mass fraction of the void galaxy population in comparison to the similar galaxies in denser environments.…”

Nearby void dwarf galaxies: recent results, the ongoing project and prospects

“…Makarov & A.L. Tepliakova of M(Hi)/L B (Pustilnik & Martin (2016)), and the comparison with the control samples in the Local Volume are as follows.…”