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