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The Structures and Kinematics of Protoclusters

The Structures and Kinematics of Protoclusters. James Di Francesco (NRC-HIA). IAU Symposium 221 Sydney, Australia July 23, 2003. Defining Protoclusters. Most stars form within clustered environments (e.g., Lada & Lada 2003)

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The Structures and Kinematics of Protoclusters

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  1. The Structures and Kinematicsof Protoclusters James Di Francesco (NRC-HIA) IAU Symposium 221 Sydney, Australia July 23, 2003

  2. Defining Protoclusters • Most stars form within clustered environments (e.g., Lada & Lada 2003) • Embedded cluster ages are <106 to ~106.5 yr, age spreads can be of same order • Protoclusters = embedded clusters of age <106 yrs and significant population of extremely embedded objects (PPCs and Class 0 YSOs)

  3. NGC 1333 Serpens Ophiuchus Porras, Christopher, Allen, Di Francesco, Megeath, & Myers 2003 Spatial Distribution of Young Stellar Clusters within 1 kpc

  4. Structure of Protoclusters • Hierarchical (e.g., NGC 2264) or centrally-condensed? (e.g., IC 348, Trapezium-ONC) • For protoclusters, near-infrared and submillimeter continuum surveys must be considered together to reveal structure

  5. Oph A Serpens Associated stellar objects “Associated” stellar objects Barsony et al. (1997): Klim = 14.0 Allen et al. (2002): Hlim = 21.0 Eiroa & Casali (1992): Klim = 15.5 Giovannetti et al. (1998): Klim = 16.3 Kaas (1999): Klim = 17.5

  6. NGC 1333 Associated stellar objects Aspin, Sandell, & Russell (1994): Klim = 16.2 (also Aspin & Sandell (1997). Lada, Alves, & Lada (1996))

  7. NGC 1333 CO 3-2 wing emission Sandell & Knee (2001) Knee & Sandell (2000)

  8. Kinematics of Protoclusters • Few, if any, near-IR studies of kinematics of YSOs in nearby protoclusters (note: see poster 1044 by Gustafsson et al.) • Kinematics obtained instead from associated gas, i.e. from molecular lines observed with heterodyne instruments • Choice of molecular tracer crucial; depletion and excitation affect molecular species very differently • N2H+ very promising; relatively little depletion, 1-0 transition excited at high density, low optical depth

  9. Oph A Serpens NW BIMA/IRAM 30m N2H+ 1-0 JCMT 850 mm BIMA/FCRAON2H+ 1-0 JCMT 850 mm Williams & Myers (2000) Testi & Sargent (1998) (also Testi et al. (2000), Olmi & Testi (2002)) Di Francesco, Andre, & Myers (2003) Motte, Andre, & Neri (1998)

  10. N2H+ 1-0 Central Line Velocitiesin Oph A rms = 0.2 km s-1 subsonic Di Francesco, Andre, & Myers (2003)

  11. NGC 1333 BIMA/FCRAON2H+ 1-0 JCMT 850 mm Walsh, Di Francesco, Myers, Bourke, & Wilner (2003) <- poster 1159 Sandell & Knee (2001)

  12. The Near Future: Large, Unbiased Surveys • Recent maps restricted in extent, sensitivity • SIRTF-c2d: Legacy project to map entirety of 5 nearby star-forming molecular clouds, obtain census of YSO populations down to 0.001 LSUN • COMPLETE: project to complement SIRTF-c2d with extensive submillimeter continuum, millimeter line, and infrared extinction maps of Serpens, Ophiuchus, and Perseus (NGC 1333)

  13. COMPLETE

  14. COMPLETE

  15. Conclusions • Recent IR and submm surveys show hierarchical structure of objects within nearby protoclusters • Influence of recent SF on current SF suggested • Kinematic studies of YSO populations are needed • Kinematic studies of dense gas show narrow ranges of velocities where stars are currently forming • New surveys will reveal entire PPC/YSO populations within nearby clouds containing protoclusters

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