The Cold Universe:
Science Highlights from theSCUBA-2 Camera
Kate Pattle
Royal Society University Research Fellow
University College London

Tsukuba Global Science Week ‒ 27th September 2022

The ColdUniverse
Dense clouds of cold(<100K) molecularhydrogen in which
new stars form
The H2 gas is mixed
with “dust” ‒silicates andcarbonaceouscompounds ‒ whichemits nearblackbody radiation

Dust emission in the Local Universe
Dust at~10-15 K

100s-1000s
of lightyears

Far-IRRadio
0.1mm

1mm!

Dust emission at high redshift
Wuyts et al. 2012

Redshift z ~ 2Dust at ~50 K

Billions of lightyears

Far-IR
0.1mm1mm!

Radio
0.1mm1mm!

The James Clerk Maxwell Telescope• The JCMT: the largest single-dishsubmillimetre telescope in the world (15m)• Operates at the summit of Mauna Kea(~4000m)• A range of instrumentation:• SCUBA-2 camera (850µm & 450µm)• POL-2 polarimeter• HARP heterodyne array (325-375 GHz)
• Namakanui heterodyne receiver• ʻUʼu (230 GHz)
• ʻAweoweo (345 GHz)
• Member of the Event Horizon Telescope

EAO Institutional Partners:•••••

TheEast AsianObservatory

Center for Astronomical Mega-Science (CAMS) ‒China
National Astronomical Observatory of Japan(NAOJ)
Academia Sinica Institute of Astronomy andAstrophysics (ASIAA) ‒ Taiwan
Korea Astronomy and Space Science Institute (KASI)National Astronomical Research Institute of Thailand(NARIT)EAO Associate Partners:•

The University of Hong Kong (HKU)EAO Observer Institutions:•••

Viet Nam National University Ho Chi Minh City(VNUHCM)
University of Malaya (UM)Institut Teknologi Bandung (ITB) ‒ Indonesia

SCUBA-2 on theJCMT• SCUBA-2: a 10 000-pixel
bolometer camera, using transitionedge sensors• Operating simultaneously at 850µm(353 GHz; 14.1” resolution) and
450µm (667 GHz; 9.6” resolution)• Primarily traces dust continuumemission

SCUBA-2 on the JCMT: wide-field, high-resolution mappingProtostellar Variability
The Transients Survey: a long-term
SCUBA-2 monitoring program

Lee et al. 2021, ApJ 920 119

Observing nearby star forming
regions (NGC 1333, IC 348, OMC
2/3, NGC 2024, NGC 2071,Ophiuchus, Serpens Main, Serpens
South) since 2016
Providing measurements foraccretion variability of protostars

Evolved Stars
Asymptotic Giant Branch (AGB) Stars ejectmass in the form of a dusty wind.
The Nearby Evolved Stars Survey (NESS)
targets a volume-limited sample of masslosing AGB stars to derive the dust and gas
return rates in the Solar Neighborhood

The envelope of U Antilae
Dharmawardena et al. 2019,MNRAS 489 3218

Nearby Galaxies
e.g. the HASHTAG Survey: mapping dust in the Andromeda Galaxy

Smith et al. 2021, ApJS 257 52

Submillimeter-bright high-z galaxies
Deep mapping of cosmologicalfields for number counts andclustering••••

S2COSMOS: wide, 850µm,
COSMOS field
STUDIES: deep, 450µm,
COSMOS-CANDELS field
NEP: 850µm, North Ecliptic
Pole fieldS2LXS: very wide, XMM-LSSand E-COSMOS fields
Wang et al. 2017, ApJ 850 37

POL-2 on SCUBA-2• POL-2: a half-waveplate insertable
into the SCUBA-2 light path
• Provides linear polarization
measurements• Can be used to map interstellar
magnetic fields and probe dust
grain size and composition• A unique facility worldwide

Dust emission polarimetry

Far-IRRadio
0.1mm1mm!

Dust emission polarimetry

Far-IRRadio
0.1mm1mm!

Dust emission polarimetry

BDust emission polarimetry

BDust emission polarimetry

BDust emission polarimetry

BDust emission polarimetry

Polarization/magnetic field
angle:

B

Polarization fraction:

Galactic dynamos and flux freezing
Magnetic fields are amplified andmaintained by a galactic dynamo
Ion-neutral coupling means that fluxfreezing holds and the gas and magnetic
field move together despite ionization
fractions dropping to < 10-7 in thehighest-density regions of molecular
clouds (e.g. Caselli et al. 1998)
Ionization at high AV in molecular clouds
is maintained by cosmic rays
Jones et al. 2019, AJ 160 167

Magnetic fields provide resistance against, and give a
preferred direction to, gravitational collapse.
Without a magnetic field

With a strong magnetic field

Magnetic fields provide resistance against, and give a
preferred direction to, gravitational collapse.
Without a magnetic field

With a strong magnetic field

Girart et al. 2006, Science 313 821

Magnetic fields and outflow feedback
Cunningham et al. 2018
MNRAS 476 771

Without a magnetic field

With a magnetic field

Magnetic fields and stellar feedback

Without a magnetic field

With a magnetic field
Geen et al. 2015, MNRAS 454 4484

The JCMT BISTRO Survey•

A James Clerk Maxwell Telescope (JCMT) Large Program mapping Galactic star-forming
regions in 850µm and 450µm polarized light with the POL-2 polarimeter•~180 survey members across 7 partner regions and the East Asian Observatory.

•P.I.s: Derek Ward-Thompson (UK & Ireland), Ray Furuya (Japan), Pierre Bastien (Canada),Keping Qiu (China), Woojin Kwon (Korea), Shih-Ping Lai (Taiwan)

The JCMT BISTRO Survey•

A James Clerk Maxwell Telescope (JCMT) Large Program mapping Galactic star-forming
regions in 850µm and 450µm polarized light with the POL-2 polarimeter

BISTRO Survey papers to date

Outflow/field comparison: Yen et al. 2020, ApJ 907 33

Survey paper: Ward-Thompson et al. 2017, ApJ 842 66

Ophiuchus L1689: Pattle et al. 2021, ApJ 907 88

Orion A: Pattle et al. 2017, ApJ 846 122
M16: Pattle et al. 2018, ApJL 860 L6

Auriga: Ngoc et al. 2021, ApJ 908 10
NGC 6334: Arzoumanian et al. 2021, A&A 647 A78

Ophiuchus A: J. Kwon et al. 2018, ApJ 859 4

Taurus B213: Eswaraiah et al. 2021, ApJ 912 L27

Ophiuchus B: Soam et al. 2018, ApJ 861 65

Rosette: Könyves et al. 2021, ApJ 913 57

Ophiuchus C: Liu et al. 2019, ApJ 877 43
IC5146: Wang et al. 2019, ApJ 876 42
Perseus B1: Coudé et al. 2019, ApJ 877 88
Oph polarization fracs.: Pattle et al. 2019, ApJ 880 27
Perseus NGC 1333: Doi et al. 2020, ApJ 899 28

More Orion A: Hwang et al. 2021, ApJ 913 85
Orion B: Lyo et al. 2021, 918 85
NGC 1333 filament widths: Doi et al. 2021, ApJL 923 L9Serpens Main: W. Kwon et al. 2022, ApJ 926 163Field vs. core rotation axis: Gupta et al. 2022, ApJ 930 61
Orion B multiwavelength: Fanciullo et al. 2022, MNRAS 512 1985

Ordered and linear
fields in low-massstar-forming cores
Pattle et al. 2021
ApJ 907 88

Ophiuchus @ 150 pc
Linear resʼn: 0.01 pc

Ordered and linear
fields in low-massstar-forming cores
Pattle et al. 2021
ApJ 907 88

Fields consistently
perpendicular todense filaments
Doi et al. 2020, ApJ 899 28

Ophiuchus @ 150 pc
Linear resʼn: 0.01 pc

Perseus NGC 1333
@ 300 pc
Linear resʼn: 0.02 pc

Ordered and linear
fields in low-massstar-forming cores
Pattle et al. 2021
ApJ 907 88

Fields consistently
perpendicular todense filaments
Doi et al. 2020, ApJ 899 28

Magnetised accretion onto
high-mass star-forming ridges
Arzoumanian et al.
2021, A&A 647 A78

NGC 6334 @ 1.3 kpc
Linear resʼn: 0.09 pc

Ophiuchus @ 150 pc
Linear resʼn: 0.01 pc

Perseus NGC 1333
@ 300 pc
Linear resʼn: 0.02 pc

The first measurements of magnetic fields within
Ordered and linear
fields in low-massstar-forming cores
Pattle et al. 2021ApJ 907 88

PDR columns: fields are reshaped under feedback
Pattle et al. 2018, ApJL 860 L6

Fields consistently
perpendicular todense filaments
Doi et al. 2020, ApJ 899 28

Magnetised accretion onto
high-mass star-forming ridges
Arzoumanian et al.
2021, A&A 647 A78

NGC 6334 @ 1.3 kpc
Linear resʼn: 0.09 pc

Ophiuchus @ 150 pc
Linear resʼn: 0.01 pc

M16 @ 1.8 kpc
Linear resʼn: 0.12 pc
Perseus NGC 1333
@ 300 pc
Linear resʼn: 0.02 pc

Feedback effects: protostellar outflows• Magnetic fields in the vicinity ofoutflows may be distorted, and/ordust polarization observations may
preferentially trace magnetic fields
in outflow cavity walls• Both spectral line and dust
polarization measurements areneeded to disentangle the physics ofPattle et al. 2022, MNRAS 515 1026

the interstellar medium

Magnetic fields in nearby galaxies: M82

Credits: NASA, ESA and the Hubble Heritage Team (STScI/AURA)

Pattle et al. 2021, MNRAS 505 684

Magnetic fields in nearby galaxies: M82
The 850µm polarized dustemission appears to trace:••a poloidal magnetic field in
the central starburst at smallgalactocentric radii, anda spiral-arm-aligned or
toroidal field in the disc atlarge galactocentric radii.

Pattle et al. 2021, MNRAS 505 684

Magnetic fields in nearby galaxies: M82

Jones 2000, AJ 120 2920
Pattle et al. 2021, MNRAS 505 684

The JCMT Semester
23A Call for Proposals
is now open!
https://www.eaobservatory.org/jcmt/
2022/09/call-for-proposals-23a/

Deadline: 12th OctoberThank you!