Quasi-Periodic Formaldehyde Maser Flares in the Massive Protostellar Object IRAS18566+0408

TL;DR

This study reports the discovery of quasi-periodic formaldehyde maser flares in a massive protostellar object, revealing correlated variability with methanol masers and suggesting a link to periodic accretion in a young binary system.

Contribution

First detection of quasi-periodic formaldehyde maser flares in a massive star-forming region, with insights into their possible origin from binary accretion processes.

Findings

Discovered ~237-day periodic formaldehyde maser flares.

Found correlated variability between formaldehyde and methanol masers.

Flares likely caused by infrared radiation variations due to binary accretion.

Abstract

We report results of an extensive observational campaign of the 6 cm formaldehyde maser in the young massive stellar object IRAS18566+0408 (G37.55+0.20) conducted from 2002 to 2009. Using Arecibo, VLA, and GBT, we discovered quasi-periodic formaldehyde flares (P ~ 237 days). Based on Arecibo observations, we also discovered correlated variability between formaldehyde (H2CO) and methanol (CH3OH) masers. The H2CO and CH3OH masers are not spatially coincident, as demonstrated by different line velocities and high angular resolution MERLIN observations. The flares could be caused by variations in the infrared radiation field, possibly modulated by periodic accretion onto a young binary system.