The Structures and Kinematics of Protoclusters
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Transcript of The Structures and Kinematics of Protoclusters
The Structures and The Structures and KinematicsKinematics
of Protoclustersof Protoclusters
James Di Francesco James Di Francesco (NRC-HIA)(NRC-HIA)
IAU Symposium 221 Sydney, Australia July 23, 2003IAU Symposium 221 Sydney, Australia July 23, 2003
Defining ProtoclustersDefining Protoclusters
Most stars form within clustered environments Most stars form within clustered environments
(e.g., Lada & Lada 2003)(e.g., Lada & Lada 2003)
Embedded cluster ages are <10Embedded cluster ages are <106 6 to ~10to ~106.5 6.5 yr, yr,
age spreads can be of same orderage spreads can be of same order
ProtoclustersProtoclusters = embedded clusters of age <10 = embedded clusters of age <1066
yrs and significant population of extremely yrs and significant population of extremely
embedded objects (PPCs and Class 0 YSOs)embedded objects (PPCs and Class 0 YSOs)
Porras, Christopher, Allen, Di Francesco, Megeath, & Myers 2003
Spatial Distribution of Young Stellar Clusters within 1 kpc
Serpens
NGC 1333
Ophiuchus
Structure of ProtoclustersStructure of Protoclusters
Hierarchical (e.g., NGC 2264) or centrally-Hierarchical (e.g., NGC 2264) or centrally-
condensed? (e.g., IC 348, Trapezium-ONC)condensed? (e.g., IC 348, Trapezium-ONC)
For protoclusters, near-infrared and submillimeter For protoclusters, near-infrared and submillimeter
continuum surveys must be considered together continuum surveys must be considered together
to reveal structureto reveal structure
SerpensSerpens Oph AOph A
Associated stellar objects “Associated” stellar objects
Eiroa & Casali (1992): Klim = 15.5Giovannetti et al. (1998): Klim = 16.3Kaas (1999): Klim = 17.5
Barsony et al. (1997): Klim = 14.0Allen et al. (2002): Hlim = 21.0
NGC 1333NGC 1333
Associated stellar objects
Aspin, Sandell, & Russell (1994): Klim = 16.2(also Aspin & Sandell (1997). Lada, Alves, & Lada (1996))
NGC 1333NGC 1333
CO 3-2 wing emission
Sandell & Knee (2001)Knee & Sandell (2000)
Kinematics of ProtoclustersKinematics of Protoclusters
Few, if any, near-IR studies of kinematics of YSOs Few, if any, near-IR studies of kinematics of YSOs
in nearby protoclusters (note: see poster 1044 by in nearby protoclusters (note: see poster 1044 by
Gustafsson et al.)Gustafsson et al.)
Kinematics obtained instead from associated gas, Kinematics obtained instead from associated gas,
i.e. from molecular lines observed with heterodyne i.e. from molecular lines observed with heterodyne
instrumentsinstruments
Choice of molecular tracer crucial; depletion and Choice of molecular tracer crucial; depletion and
excitation affect molecular species very differentlyexcitation affect molecular species very differently
NN22HH++ very promising; relatively little depletion, 1-0 very promising; relatively little depletion, 1-0
transition excited at high density, low optical depthtransition excited at high density, low optical depth
Serpens Serpens NWNW Oph AOph A
BIMA/FCRAO N2H+ 1-0
JCMT 850 m
Williams & Myers (2000)Testi & Sargent (1998)(also Testi et al. (2000), Olmi & Testi (2002))
Di Francesco, Andre, & Myers (2003)Motte, Andre, & Neri (1998)
BIMA/IRAM 30m N2H+ 1-0
JCMT 850 m
NN22HH++ 1-0 Central Line Velocities 1-0 Central Line Velocitiesin Oph Ain Oph A
Di Francesco, Andre, & Myers (2003)
rms = 0.2 km s-1
subsonic
NGC 1333NGC 1333
Walsh, Di Francesco, Myers, Bourke, & Wilner (2003) <- poster 1159Sandell & Knee (2001)
BIMA/FCRAO N2H+ 1-0JCMT 850 m
The Near Future: The Near Future: Large, Unbiased SurveysLarge, Unbiased Surveys
Recent maps restricted in extent, sensitivityRecent maps restricted in extent, sensitivity
SIRTF-c2d:SIRTF-c2d: Legacy project to map entirety of 5 Legacy project to map entirety of 5
nearby star-forming molecular clouds, obtain nearby star-forming molecular clouds, obtain
census of YSO populations down to 0.001 Lcensus of YSO populations down to 0.001 LSUNSUN
COMPLETE:COMPLETE: project to complement project to complement SIRTF-c2dSIRTF-c2d with with
extensive submillimeter continuum, millimeter extensive submillimeter continuum, millimeter
line, and infrared extinction maps of Serpens, line, and infrared extinction maps of Serpens,
Ophiuchus, and Perseus (NGC 1333)Ophiuchus, and Perseus (NGC 1333)
COMPLETE
COMPLETE
ConclusionsConclusions
Recent IR and submm surveys show hierarchical Recent IR and submm surveys show hierarchical
structure of objects within nearby protoclustersstructure of objects within nearby protoclusters
Influence of recent SF on current SF suggestedInfluence of recent SF on current SF suggested
Kinematic studies of YSO populations are neededKinematic studies of YSO populations are needed
Kinematic studies of dense gas show narrow Kinematic studies of dense gas show narrow
ranges of velocities where stars are currently ranges of velocities where stars are currently
formingforming
New surveys will reveal entire PPC/YSO populations New surveys will reveal entire PPC/YSO populations
within nearby clouds containing protoclusterswithin nearby clouds containing protoclusters