Figure 1.
Gemini North / NIRI
infrared image of NGC
2071-IR in the combined
light of the broad J,
H, and K filters and a
narrow band filter at
the wavelength of a
line of shock-excited
molecular hydrogen
(H 2 ). The resolution of
the image is ~0.40”, at
least three times higher
than any previously
obtained images of the
region. The field of view
is 2’ x 2’. North is up and
East is to the left. Most
of the finely structured
emission is from H 2 ,
while the more smoothly
distributed emission is
the combined light of H 2
and starlight scattered
off of dust particles.
Identified protostars
have been labelled.
Color composite image
created by Gemini
Science Operations
Specialist Jennifer Miller.
To help identify the young culprits respon-
sible for disrupting the core of NGC 2071,
Walther and I used the Gemini North Near-
InfraRed Imager and spectrometer (NIRI)
in 2017 and 2018 to dig deeper into the
complex region. Figure 1 shows our results
— the sharpest composite infrared image
ever obtained of the region. We combined
images taken individually through several
filters — one of which was sensitive to the
emission of hot molecular hydrogen (H 2 ).
Putting them together created a coherent
picture.
Stars, light from glowing gas, and light re-
flected off of dust particles are readily ap-
parent in the image. The complex V-shaped
structure extending from the center of the
image toward the upper left, whose left arm
extends across the positions of IRS 2 A&B
10
GeminiFocus
and IRS 6 A&B, is emitted by shock-heated
molecular hydrogen, where gas ejected
from a protostar is colliding with quiescent
gas in the surrounding cloud. A fainter V
extension can be seen at lower right. Both
extend far beyond the edges of the image.
Such “bipolar outflows” of gas are common-
ly observed from stars accreting material
from their natal clouds.
While it was originally supposed that IRS 1,
by far the most luminous and likely the most
massive protostar in NGC 2071-IR, was gen-
erating this bipolar outflow, these new data,
along with radio and infrared observations
published by other scientists, strongly sug-
gest that the less luminous IRS 3 is the culprit.
To the left of the center of the image lies the
brightest region of H 2 line emission in NGC
2071-IR, which others had recently suggest-
ed might be associated with IRS 1. In our pa-
January 2020 / 2019 Year in Review