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Dr Sven Van Loo

Astrophysics Group

Contact details

Room: 9.76
Tel: +44 (0)113 3434864
Email: S.VanLoo @ leeds.ac.uk

Keywords

Dusty plasmas
Star formation
Hydrodynamics and magnetohydrodynamics
Numerical simulations

Research interests

Formation and evolution of GMCs:

Molecular clouds exhibit a hierarchical density structure with stars forming in their densest regions. Often, these star-forming complexes have an elongated, filamentary shape. Star formation occurs primarily in these GMCs, but is usually restricted to a small fraction of the volume of a GMC, as most stars form in or near relatively small clusters. This would seem to suggest that the processes setting the Galactic star formation rate are those that generate and/or destruct the dense clumps within GMCs. In contrast, the observationally inferred Kennicutt relation implies that the rate depends on a large-scale average of the column density of interstellar gas, which points to the importance of processes acting on scales larger than GMCs in regulating the Galactic rate. The star formation rate is thus closely linked to the dynamics of the interstellar medium (ISM) and thus directly regulated by processes like gravitational, thermal and magnetohydrodynamical instabilities and stellar feedback. Using numerical simulations I study the formation and evolution of GMCs in isolation and within the context of galaxies.

Multifluid shocks:

I study the dynamics of shock waves in magnetised and dusty plasmas. These models are relevant to the study of the outflows near young stellar objects. We have developed a time- dependent multiuid MHD code to calculate the structure of steady perpendicular and oblique C-type shocks in dusty plasmas. These models are the first of oblique fast-mode molecular shocks in which a rigorous treatment of the dust dynamics has been combined with a self-consistent calculation of the thermal and ionisation structures including appropriate microphysics. A time-dependent method is not only robust for finding steady state shock structures. It is also vital for modelling transient phenomena such as the interaction of a shock with a dense clump in a molecular cloud. Recently, we included grain sputtering in oblique C-type shocks to model the release of Silicon in the gas phase in order to compare with observations. Currently, I am working on 2D and 3D models of C-type shocks.

Publications

Wu B, Tan JC, Nakamura F, Van Loo S, Christie D, Collins D GMC Collisions as Triggers of Star Formation. II. 3D Turbulent, Magnetized Simulations Astrophysical Journal 835 1-23, 2017
DOI:10.3847/1538-4357/835/2/137
View abstract

Burge CA, Van Loo S, Falle SAEG, Hartquist TW Ambipolar diffusion regulated collapse of filaments threaded by perpendicular magnetic fields Astronomy and Astrophysics 596 -, 2016
DOI:10.1051/0004-6361/201629039
View abstract

Wareing CJ, Pittard JM, Falle SAEG, Van Loo S Magnetohydrodynamical simulation of the formation of clumps and filaments in quiescent diffuse medium by thermal instability Monthly Notices of the Royal Astronomical Society 459 1803-1818, 2016
DOI:10.1093/mnras/stw581
View abstract

Wu B, Van Loo S, Tan JC, Bruderer S GMC COLLISIONS AS TRIGGERS OF STAR FORMATION. I. PARAMETER SPACE EXPLORATION WITH 2D SIMULATIONS ASTROPHYSICAL JOURNAL 811 -, 2015
DOI:10.1088/0004-637X/811/1/56

Butler MJ, Tan JC, Van Loo S KILOPARSEC-SCALE SIMULATIONS OF STAR FORMATION IN DISK GALAXIES. III. STRUCTURE AND DYNAMICS OF FILAMENTS AND CLUMPS IN GIANT MOLECULAR CLOUDS ASTROPHYSICAL JOURNAL 805 -, 2015
DOI:10.1088/0004-637X/805/1/1

Van Loo S, Tan JC, Falle SAEG MAGNETIC FIELDS AND GALACTIC STAR FORMATION RATES ASTROPHYSICAL JOURNAL LETTERS 800 -, 2015
DOI:10.1088/2041-8205/800/1/L11

Van Loo S, Keto E, Zhang Q Core and filament formation in magnetized, self-gravitating isothermal layers Astrophysical Journal 789 -, 2014
DOI:10.1088/0004-637X/789/1/37
View abstract

Van Loo S, Butler MJ, Tan JC Kiloparsec-scale simulations of star formation in disk galaxies. I. the unmagnetized and zero-feedback limit Astrophysical Journal 764 -, 2013
DOI:10.1088/0004-637X/764/1/36
View abstract

Van Loo S, Ashmore I, Caselli P, Falle SAEG, Hartquist TW Sputtering in oblique C-type shocks Monthly Notices of the Royal Astronomical Society 428 381-388, 2013
DOI:10.1093/mnras/sts030
View abstract

Van Loo S, Hartquist TW, Falle SAEG Magnetic fields and star formation Astronomy and Geophysics 53 -, 2012
DOI:10.1111/j.1468-4004.2012.53531.x
View abstract

Tan JC, Shaske SN, Van Loo S Molecular clouds: Internal properties, turbulence, star formation and feedback Proceedings of the International Astronomical Union 8 19-28, 2012
DOI:10.1017/S1743921313000173
View abstract

Ashmore I, Van Loo S, Caselli P, Falle SAEG, Hartquist TW Transient evolution of C-type shocks in dusty regions of varying density Astronomy and Astrophysics 511 -, 2010
DOI:10.1051/0004-6361/200913277
View abstract

Van Loo S, Falle SAEG, Hartquist TW Shock-triggered formation of magnetically dominated clouds - II. Weak shock-cloud interaction in three dimensions MON NOT R ASTRON SOC 406 1260-1268, 2010
DOI:10.1111/j.1365-2966.2010.16761.x

Jimenez-Serra I, Caselli P, Tan JC, Hernandez AK, Fontani F, Butler MJ, van Loo S Parsec-scale SiO emission in an infrared dark cloud MON NOT R ASTRON SOC 406 187-196, 2010
DOI:10.1111/j.1365-2966.2010.16698.x

Van Loo S, Falle SAEG, Hartquist TW, Havnes O, Morfill GE Dusty magnetohydrodynamics in star-forming regions J PLASMA PHYS 76 569-578, 2010
DOI:10.1017/S0022377809990894

Ashmore I, Van Loo S, Caselli P, Falle SAEG, Hartquist TW Transient evolution of C-type shocks in dusty regions of varying density ASTRON ASTROPHYS 511 -, 2010
DOI:10.1051/0004-6361/200913277

Hartquist TW, van Loo S, Falle SAEG HOW INTERSTELLAR CHEMISTRY (AND ASTROCHEMISTRY MORE GENERALLY) BECAME USEFUL, 2010

Van Loo S Non-Thermal Radio Emission from 'Presumably' Single O Stars, 2010

Van Loo S, Ashmore I, Caselli P, Falle SAEG, Hartquist TW Time-dependent simulations of steady C-type shocks MON NOT R ASTRON SOC 395 319-327, 2009
DOI:10.1111/j.1365-2966.2009.14515.x

Falle SAEG, Hartquist TW, van Loo S Numerical Simulations of the Wardle Instability, 2009

Van Loo S, Falle SAEG, Hartquist TW, Barker AJ The effect of ambipolar resistivity on the formation of dense cores ASTRON ASTROPHYS 484 275-280, 2008
DOI:10.1051/0004-6361:200809432

Van Loo S, Blomme R, Dougherty SM, Runacres MC Non-thermal radio emission from O-type stars - III. Is Cygnus OB2 no. 9 a wind-colliding binary? ASTRON ASTROPHYS 483 585-U39, 2008
DOI:10.1051/0004-6361:200809367

Hartquist TW, Van Loo S, Falle SAEG, Caselli P, Ashmore I Dust in interstellar clouds, evolved stars and supernovae, 2008

Van Loo S, Falle S, Hartquist TW, Moore TJT Shock-triggered formation of magnetically dominated clouds Astronomy and Astrophysics 471 213-218, 2007
DOI:10.1051/0004-6361:20077430

Van Loo S, Falle SAEG, Hartquist TW Dense core compression and fragmentation induced by the scattering of hydromagnetic waves MON NOT R ASTRON SOC 376 779-784, 2007
DOI:10.1111/j.1365-2966.2007.11472.x

Blomme R, De Becker M, Runacres MC, Van Loo S, Gunawan DYAS Non-thermal radio emission from O-type stars ASTRON ASTROPHYS 464 701-U148, 2007
DOI:10.1051/0004-6361:20054602

Van Loo S Non-thermal radio emission from O stars: Binary versus single, 2007
View abstract

Van Loo S Are all non-thermal radio-emitting O-stars binaries?, 2007
View abstract

De Becker M, Rauw G, Sana H, Pollock AMT, Pittard JM, Blomme R, Stevens IR, Van Loo S XMM-Newton observations of the massive colliding wind binary and non-thermal radio emitter Cyg OB2#8A [O6If+O5.5III(f)] MON NOT R ASTRON SOC 371 1280-1294, 2006
DOI:10.1111/j.1365-2966.2006.10746.x

Van Loo S, Falle SAEG, Hartquist TW Generation of density inhomogeneities by magnetohydrodynamic waves in two dimensions MON NOT R ASTRON SOC 370 975-980, 2006
DOI:10.1111/j.1365-2966.2006.10524.x

Van Loo S, Falle SAEG, Hartquist TW The generation of dense cores and substructure within them by MHD waves Proceedings of the International Astronomical Union 2 486-, 2006
DOI:10.1017/S1743921307002748
View abstract

Van Loo S, Runacres MC, Blomme R Can single O stars produce non-thermal radio emission? Astronomy and Astrophysics 452 1011-1019, 2006
DOI:10.1051/0004-6361:20054266
View abstract

Van Loo S, Runacres MC, Blomme R Can single O stars produce non-thermal radio emission? ASTRON ASTROPHYS 452 1011-1019, 2006
DOI:10.1051/0004-6361

Blomme R, Van Loo S, De Becker M, Rauw G, Runacres MC, Gunawan DYAS, Chapman JM Non-thermal radio emission from Otype stars ASTRON ASTROPHYS 436 1033-1040, 2005
DOI:10.1051/0004-6361:20042383

Van Loo S, Runacres MC, Blomme R A layered model for non-thermal radio emission from single O stars ASTRON ASTROPHYS 433 313-322, 2005
DOI:10.1051/0004-6361:20041973

De Becker A, Rauw G, Blomme R, Waldron WL, Sana H, Pittard JM, Eenens P, Stevens IR, Runacres MC, Van Loo S, Pollock AMT Quasi-simultaneous XMM-Newton and VLA observation of the non-thermal radio emitter HD 168112 (05.5III(f(+))) ASTRON ASTROPHYS 420 1061-1077, 2004
DOI:10.1051/0004-6361:20041030

Van Loo S, Runacres MC, Blomme R Non-thermal radio emission from single hot stars ASTRON ASTROPHYS 418 717-725, 2004
DOI:10.1051/0004-6361:20034480

Van Loo S Non-thermal radio emission from single hot stars Revista Mexicana de Astronomia y Astrofisica: Serie de Conferencias 15 230-, 2003
View abstract

Rauw G, Blomme R, Waldron WL, Corcoran MF, Pittard JM, Pollock AMT, Runacres MC, Sana H, Stevens IR, Van Loo S A multi-wavelength investigation of the non-thermal radio emitting O-star 9 Sgr ASTRON ASTROPHYS 394 993-1008, 2002
DOI:10.1051/0004-6361:20020926