A shallow though extensive H2 2.12 micron imaging survey of Taurus-Auriga-Perseus: I. NGC1333, L1455, L1448 and B1

TL;DR

This study presents a comprehensive near-infrared imaging survey of star-forming regions in Perseus, identifying numerous molecular outflows and their sources, and analyzing their properties and correlations with cloud mass and star formation activity.

Contribution

It provides the first extensive H2 2.12 micron imaging survey of multiple Perseus regions, linking outflows with embedded Spitzer sources and analyzing outflow characteristics and their relation to cloud properties.

Findings

85 H2 features detected, associated with 26 outflows

Three parsec-scale flows identified with mean length >11.5 arcmin

High IR spectral indices and red colors effectively identify outflow sources

Abstract

We discuss wide-field near-IR imaging of the NGC1333, L1448, L1455 and B1 star forming regions in Perseus. The observations have been extracted from a much larger narrow-band imaging survey of the Taurus-Auriga-Perseus complex. These H2 2.12 micron observations are complemented by broad-band K imaging, mid-IR imaging and photometry from the Spitzer Space Telescope, and published submillimetre CO J=3-2 maps of high-velocity molecular outflows. We detect and label 85 H2 features and associate these with 26 molecular outflows. Three are parsec-scale flows, with a mean flow lobe length exceeding 11.5 arcmin. 37 (44%) of the detected H2 features are associated with a known Herbig-Haro object, while 72 (46%) of catalogued HH objects are detected in H2 emission. Embedded Spitzer sources are identified for all but two of the 26 molecular outflows. These candidate outflow sources all have high near-to-mid-IR spectral indices (mean value of alpha ~ 1.4) as well as red IRAC 3.6-4.5 micron and IRAC/MIPS 4.5-24.0 micron colours: 80% have [3.6]-[4.5] > 1.0 and [4.5]-[24] > 1.5. These criteria - high alpha and red [4.5]-[24] and [3.6]-[4.5] colours - are powerful discriminants when searching for molecular outflow sources. However, we find no correlation between alpha and flow length or opening angle, and the outflows appear randomly orientated in each region. The more massive clouds are associated with a greater number of outflows, which suggests that the star formation efficiency is roughly the same in each region.