Extragalactic maser surveys

TL;DR

Recent advancements and upcoming prospects in extragalactic maser surveys have significantly improved sensitivity and expanded the scope of molecular line studies using major radio observatories.

Contribution

This paper reviews recent progress, current projects, and future outlooks in extragalactic maser surveys with advanced radio telescopes.

Findings

Enhanced sensitivity enables dedicated maser surveys.

Expansion of molecular line studies with new radio arrays.

Growing potential for extragalactic maser research in upcoming years.

Abstract

Since the IAU (maser-)Symposium 287 in Stellenbosch/South Africa (Jan. 2012), great progress has been achieved in studying extragalactic maser sources. Sensitivity has reached a level allowing for dedicated maser surveys of extragalactic objects. These included, during the last years, water vapor (H2O), methanol (CH3OH), and formaldehyde (H2CO), while surveys related to hydroxyl (OH), cyanoacetylene (HC3N) and ammonia (NH3) may soon become (again) relevant. Overall, with the upgraded Very Large Array (VLA), the Atacama Large Millimeter/submillimeter Array (ALMA), FAST (Five hundred meter Aperture Synthesis Telescope) and the low frequency arrays APERTIF (APERture Tile in Focus), ASKAP (Australian Square Kilometer Array Pathfinder) and MeerKAT (Meer Karoo Array Telescope), extragalactic maser studies are expected to flourish during the upcoming years. The following article provides a brief sketch of past achievements, ongoing projects and future perspectives.