Dynamics of Planetary Rings and Galaxies
(Prof. Heikki Salo, Division of Astronomy , Department of Physics , University of Oulu , Finland)

• Planetary ring dynamics
• Satellite resonances
• Dynamics and observations of interacting galaxies
• Dynamics of barred galaxies
• Development of numerical N-body simulation methods

At the moment the group consists of following members:

• Prof. Heikki Salo (planetary rings, galaxy dynamics and observations)
• Dr., Dos. Eija Laurikainen (galaxy dynamics and observations)
• Dr. Juergen Schmidt (planetary rings and satellites, dust dynamics)
• Dr., Dos. Pertti Rautiainen (galaxies)
• Dr. Sebastien Comeron (galaxies)
• Dr. Joachim Janz
• MSc. Jarkko Laine
• MSc. Simon Diaz
• MSc. Martin Herrera
• + undergraduate students (Juho Montonen, Aku Venhola)

Former members of the group:

• Dr., Dos. Jyrki Hänninen (planetary rings)
• Dr. Ryuji Morishima (planetary rings)
• Dr. Raine Karjalainen (planetary rings)
• PhD Patrick Treuthard (galaxies)
• PhD Rebecca Grouchy (galaxies)

The most important current collaborations are with the University of Alabama (Ron Buta), the Wellesley College (Richard French, Colleen McGhee), the Cornell university (Phil Nicholson, Matt Hedman), the University of Potsdam (Frank Spahn), and the University of Colorado at Boulder (Miodrag Sremcevic, Nicole Albers). We are also participating to the S4G survey (PI Kartik Sheth: The Spitzer Survey of Stellar Structure in Galaxies).

Our recent planetary ring studies have concentrated on dense rings, especially the role of self-gravity. The most important result has been the numerical prediction of small-scale wake structure in Saturns's rings (Nature 359, 619). We are investigating the observational implications of such wakes with photometric MC-simulation, and comparing the results to Voyager data, and to HST observations by Dick French. Other current interest is the apparantly irregular density variations in Saturn's B-ring: we are studying the properties of such extremely dense rings both with N-body simulations and with hydrodynamical stability analysis, in collaboration with Frank Spahns's group in Potsdam.

Our previous satellite resonance studies have dealt with the angular momentum exchange between rings and satellites, confirming numerically the validity of Goldreich-Tremaine predictions, and to some degree extending them to non-linear regime. Also, we have demonstrated the possibility of one-sided confinement of narrow ringlet in the 2:1 ILR of external satellite. Our recent studies have dealt with the azimuthally incomplete ring arcs of Neptune. We have shown (Science 282, 1102) that self-gravity of massive arc particles can stabilize them agains mutual impacts, and help to confine dust to the arc region in general. We are currently seaking for possible explanations for the recently observed shift between the locations of the arcs and the predictions of the Porco-Goldreich-Tremaine-model.

Our studies of interacting galaxies concentrate on the observed properties and N-body modelling of M51-type closely interacting galaxies. Observations include both visual and IR broad-band imaging, and Fabry-Perot velocity fields. Fairly detailed tidal models have been constructed for two systems, Arp 86 and the M51 itself. Our current interests concentrate on the innermost spiral structures, and the interplay between intrinsic spiral modes and externally induced tidal waves.

The other main application of our N-body modelling of galaxies have been the barred galaxies , especially the ring structures related to the resonances of the rotating bar. For example, a detailed N-body model has been developed for IC 4214, a prototypical weakly barred galaxy, using ring morphology and kinematics as diagnostics for the bar strength and pattern speed. Recent studies concentrate on the outer spiral modes, and their relation to the dominant bar mode: for example we address the non-linear mode coupling.

We are also studying the observed properties of bars in collaboration with Ron Buta, and their correlations with the gravitational perturbations associated with bars, derived from near IR-images.

Starting almost 20 years ago, various N-body methods have been developed in our group, first for planetary ring simulations and later also for galaxy studies. The main current methods include

• Local simulations of planetary rings, including dissipative collisions and self-gravity.
• Numerical codes for long-term integration of particle-satellite interactions, including radiative pressure.
• 3D multi-grid code for simulation of interacting galaxies, composed of self-consistent disk+bulge+halo systems with both stars and gas.

Recent Publications in referee journals:

2014:

• [1] Comerón S., Elmegreen B. G., Salo H., Laurikainen E., Holwerda B. W., Knapen J. H.: Evidence for the concurrent growth of thick discs and central mass concentrations from S4G imaging, Astron. Astrophys., 571, A58 (16 pp), 2014 [10.1051/0004-6361/201424412]
• [2] Comerón S., Salo H., Laurikainen E., Knapen J.H., Buta R.J., Herrera-Endoqui M., Laine J., Holwerda B.W., Sheth K., Regan M.W., Hinz J.L., Muñoz-Mateos J.-C., Gil de Paz A., Menéndez-Delmestre K., Seibert M., Mizusawa T., Kim T., Erroz-Ferrer S., Gadotti D.A., Athanassoula E., Bosma A., Ho L.C.: ARRAKIS: atlas of resonance rings as known in the S4G, Astron. Astrophys., 562, A121 (160 pp), 2014 [10.1051/0004-6361/201321633]
• [3] Elmegreen D.M., Elmegreen B.G., Erroz-Ferrer S., Knapen, J.H., Teich Y., Popinchalk M., Athanassoula E., Bosma, A., Comerón S., Efremov Y.N., Gadotti D.A., Gil de Paz A., Hinz J.L., Ho L.C., Holwerda B., Kim T., Laine J., Laurikainen E., Menéndez-Delmestre K., Mizusawa T., Muñoz-Mateos J.-C., Regan M.W., Salo H., Seibert M., Sheth K.: Embedded Star Formation in S4G Galaxy Dust Lanes, Astrophys. J., 780, 32 (12 pp), 2014 [10.1088/0004-637X/780/1/32]
• [4] Hedman M. M., Nicholson P. D., Salo H.: Exploring Overstabilities in Saturn$(B!l(Bs A Ring Using Two Stellar Occultations, Astron. J., 148, 15 (9 pp), 2014 [10.1088/0004-6256/148/1/15]
• [5] Holwerda B. W., Muñoz-Mateos J.-C., Comerón S., Meidt S., Sheth K., Laine S., Hinz J. L., Regan M. W., Gil de Paz, A., Menéndez-Delmestre, K., Seibert M., Kim T., Mizusawa T., Laurikainen E., Salo H., Laine J., Gadotti D. A., Zaritsky D., Erroz-Ferrer S., Ho L. C., Knapen J. H., Athanassoula E., Bosma A., Pirzkal N.: Morphological Parameters of a Spitzer Survey of Stellar Structure in Galaxies, Astrophys. J., 781, 12 (19 pp), 2014 [10.1088/0004-637X/781/1/12]
• [6] Janz, J., Laurikainen, E., Lisker, T., Salo, H., Peletier, R. F., Niemi, S.-M., Toloba, E., Hensler, G., Falcón-Barroso, J., Boselli, A., den Brok, M., Hansson, K. S. A., Meyer, H. T., Ry-B¶, A., Paudel, S.: A Near-infrared Census of the Multicomponent Stellar Structure of Early-type Dwarf Galaxies in the Virgo Cluster, Astrophys. J., 786, 105 (33 pp), 2014 [10.1088/0004-637X/786/2/105]-A
• [7] Kim T., Gadotti D.A., Sheth K., Athanassoula E., Bosma A., Lee M.G., Madore B.F., Elmegreen B:, Knapen J.H., Zaritsky D., Ho L.C., Comerón S., Holwerda B., Hinz J.L., Muñoz-Mateos J.-C., Cisternas M., Erroz-Ferrer S., Buta R., Laurikainen E., Salo H., Laine J., Menéndez-Delmestre K., Regan M.W., de Swardt B., Gil de Paz A., Seibert M., Mizusawa T.: Unveiling the Structure of Barred Galaxies at 3.6 -Fìm with the Spitzer Survey of Stellar Structure in Galaxies (S4G). I. Disk Breaks, Astrophys. J., 782, 64 (19 pp), 2014 [10.1088/0004-637X/782/2/64]-A
• [8] Laine, J., Laurikainen, E., Salo, H., Comerón, S., Buta, R. J., Zaritsky, D., Athanassoula, E., Bosma, A., Muñoz-Mateos, J.-C., Gadotti, D. A., Hinz, J. L., Erroz-Ferrer, S., Gil de Paz, A., Kim, T., Menéndez-Delmestre, K., Mizusawa, T., Regan, M. W., Seibert, M., Sheth, K.: Morphology and environment of galaxies with disc breaks in the S4G and NIRS0S, Mon. Not. R. Astron. Soc., 441, 1992 (21 pp), 2014 [10.1093/mnras/stu628]
• [9] Laine S., Knapen J. H., Muñoz-Mateos J.-C., Kim T., Comerón S., Martig M., Holwerda B. W., Athanassoula E., Bosma A., Johansson P. H., Erroz-Ferrer S., Gadotti D. A., Gil de Paz A., Hinz J., Laine J., Laurikainen E., Menéndez-Delmestre K., Mizusawa T., Regan M. W., Salo H., Sheth K., Seibert M., Buta R. J., Cisternas M., Elmegreen B. G., Elmegreen D. M., Ho L. C., Madore B. F., Zaritsky D.: Spitzer/Infrared Array Camera near-infrared features in the outer parts of S4G galaxies, Mon. Not. R. Astron. Soc., 444, 3015-3039, 2014 [10.1093/mnras/stu1642]
• [10] Laurikainen E., Salo H., Athanassoula E., Bosma A., Herrera-Endoqui M.: Milky Way mass galaxies with X-shaped bulges are not rare in the local Universe, Mon. Not. R. Astron. Soc., 444, 80-84, 2014 [10.1093/mnrasl/slu118]
• [11] Meidt, S., Schinnerer, E, van de Ven, G., Zaritsky,D., Peletier, R., Knapen, J.H., Sheth, K., Regan, M., Querejeta, M., Muñoz-Mateos, J.-C., Kim, T., Hinz, J.L., Gil de Paz, A., Athanassoula, E., Bosma, A., Buta, R., Cisternas, M., Ho, L.C.., Holwerda, B., Skibba, R., Laurikainen, E., Salo, H., Gadotti, D. A., Laine, J., Erroz-Ferrer, S., Comerón, S., Menéndez-Delmestre, K., Seibert, M., Mizusawa, T.: Reconstructing the Stellar Mass Distributions of Galaxies Using S4G IRAC 3.6 and 4.5 -Fìm Images. II. The Conversion from Light to Mass, Astrophys. J., 788, 144 (12 pp), 2014 [10.1088/0004-637X/788/2/144]-A
• [12] Meyer, H. T., Lisker, T., Janz, J., Papaderos, P.: What will blue compact dwarf galaxies evolve into?, Astron. Astrophys., 562, A49 (22 pp), 2014 [10.1051/0004-6361/201220700]
• [13] Toloba E., Guhathakurta P., van de Ven G., Boissier S., Boselli A., den Brok M., Falcón-Barroso J., Hensler G., Janz J., Laurikainen E., Lisker T., Paudel S., Peletier R. F., Ry-B¶ A., Salo H.: Stellar Kinematics and Structural Properties of Virgo Cluster Dwarf Early-type Galaxies from the SMAKCED Project. I. Kinematically Decoupled Cores and Implications for Infallen Groups in Clusters, Astrophys. J., 783, 120 (12 pp), 2014 [10.1088/0004-637X/783/2/120]-A
• [14] Zaritsky, D., Courtois, H., Muñoz-Mateos, J.-C., Sorce, J., Erroz-Ferrer, S., Comerón, S., Gadotti, D. A., Gil de Paz, A., Hinz, J. L., Laurikainen, E., Kim, T., Laine, J., Menéndez-Delmestre, K., Mizusawa, T., Regan, M. W., Salo, H., Seibert, M., Sheth, K., Athanassoula, E., Bosma, A., Cisternas, M., Ho, Luis C., Holwerda, B.: The Baryonic Tully-Fisher Relationship for S4G Galaxies and the "Condensed" Baryon Fraction of Galaxies, Astron. J., 147, 134 (11 pp), 2014 [10.1088/0004-6256/147/6/134]

  2013:

• Cisternas, M., Gadotti D.A., Knapen J.H., Kim T., Diaz-Garcia S., Laurikainen E., Salo H ., Gonzalez-Martin O., Ho L.C., Elmegreen B.G., Zaritsky D., Sheth K., Athanassoula E., Bosma A., Comeron S. , Erroz-Ferrer S., Gil de Paz A., Hinz J.L., Holwerda B.W., Laine J. , Meidt S., Menendez-Delmestre K., Mizusawa T., Munoz-Mateos, J.C, Regan M.W., Seibert M.: X-Ray Nuclear Activity in S4G Barred Galaxies: No Link between Bar Strength and Co-occurrent Supermassive Black Hole Fueling, Astrophys. J., 776, 50 (15 pp), 2013
• Comeron, S. : Inner rings in disc galaxies: dead or alive, Astron. Astrophys., 555, L4 (9 pp), 2013
• Laurikainen, E. H. Salo, E. Athanassoula, A. Bosma, R. Buta, J. Janz: Statistics of the structure components in S0s: implications for bar-induced secular evolution, Mon. Not. R. Astron. Soc., 430, 3489-3509, 2013
• Lisker T., Weinmann S.M., Janz J. , Meyer, H.T: Dwarf galaxy populations in present-day galaxy clusters - II. The history of early-type and late-type dwarfs, Mon. Not. R. Astron. Soc., 432, 1162-1177, 2013
• Melnik A.M., P. Rautiainen : Straight segments in the galactic discs, Mon. Not. R. Astron. Soc., 434, 1362-1375, 2013
• Munoz-Mateos J.C., Sheth K., Gil de Paz A., Meidt S., Athanassoula E., Bosma A., Comeron S. , Elmegreen D.M., Elmegreen B.G., Erroz-Ferrer S., Gadotti D.A., Hinz J.L., Ho L.C., Holwerda B., Jarrett T.H., Kim T., Knapen J.H., Laine J., Laurikainen E. Madore B.F., Menendez-Delmestre K., Mizusawa T., Regan M., Salo H. , Schinnerer E., Seibert M., Skibba R., Zaritsky D : The Impact of Bars on Disk Breaks as Probed by S4G Imaging, Astrophys. J., 771, 59 (30 pp), 2013
• Pihajoki P., M. Valtonen, S. Zola, A. Liakos, M. Drozdz, M. Winiarski, W. Ogloza, D. Koziel-Wierzbowska, J. Provencal, K. Nilsson, A. Berdyugin, E. Lindfors, R. Reintha, A. Sillanpaa, L. Takalo, M. M. M. Santangelo, H. Salo, S. Chandra, S. Ganesh, K. S. Baliyan, S. A. Coggins-Hill, A. Gopakumar: Precursor flares in OJ 287, Astrophys. J., 764, 5, 2013
• Tiscareno M.S., C.J. Mitchell, C.D. Murray, D. Di Nino, M.M. Hedman, J. Schmidt, J.A. Burns, J.N. Cuzzi, C.C. Porco, K. Beurle, M.W. Evans: Observations of Ejecta Clouds Produced by Impacts onto Saturn'ss Rings, Science, 340, 460, 2013
• Zaritsky D., Salo H., Laurikainen E. , Elmegreen D., Athanassoula E., Bosma A., Comeron S. , Erroz-Ferrer S., Elmegreen B., Gadotti D.A., Gil de Paz A., Hi nz J.L., Ho L.C., Holwerda B.W., Kim T., Knapen J.H., Laine J ., Laine S., Madore B.F., Meidt S., Menendez-Delmestre K., Mizusawa T., Munoz-Mateos J.C., Regan M.W., Seibert M., Sheth K.: On the Origin of Lopsidedness in Galaxies as Determined from the Spitzer Survey of Stellar Structure in Galaxies (S4G), Astrophys. J., 772, 135 (16 pp), 2013

  2012:

• Salo, H , (2012) : Simulating the formation of fine-scale structure in Saturn's Rings Prog. Theor Phys. Suppl., in press.
• Erroz-Ferrer, S., Knapen, J.H., Font, J., Beckman, J.E., Falcon-Barroso, J., Sanchez-Gallego, J.R., Athanassoula, E., Bosma, A., Gadotti, D.A., Muñoz-Mateos, J.-C., and 15 coauthors (2012): Halpha kinematics of S4G spiral galaxies - I. NGC 864.MNRAS, 427,2938-2949.
• Martín-Navarro, I., Bakos, J., Trujillo, I., Knapen, J.H., Athanassoula, E., Bosma, A., Comerón, S., Elmegreen, B.G., Erroz-Ferrer, S., Gadotti, D.A., and 14 coauthors (2012) : A unified picture of breaks and truncations in spiral galaxies from SDSS and S4G imagingMNRAS, 427, 1102-1134.
• Comerón, S., Elmegreen, B.G., Salo, H., Laurikainen, E., Athanassoula, E., Bosma, A., Knapen, J.H., Gadotti, D.A., Sheth, K., Hinz, J.L., and 10 coauthors (2012) ) Breaks in Thin and Thick Disks of Edge-on Galaxies Imaged in the Spitzer Survey Stellar Structure in Galaxies (S4G). ApJ, 759, 98, 29 pp.
• Mel'nik, A. M, Rautiainen, P. (2012) : Modelling of the galactic kinematics. Astronomical & Astrophysical Transactions, 2, 389-398
• Treuthardt, P., Seigar, M:S., Sierra, A.D., Al-Baidhany, I., Salo, H., Kennefick, D., Kennefick, Julia, L,, Claud H.S. (2012). On the link between central black holes, bar dynamics and dark matter haloes in spiral galaxies MNRAS, 423, 3118-3133.
• Kim,T. Sheth, K, Hinz, J.L., Lee, M.G., Zaritsky, D., Gadotti, D.A., Knapen, J.H., Schinnerer, E., Ho, L.C., Laurikainen, E., and 14 coauthors (2012) : Early-type Galaxies with Tidal Debris and Their Scaling Relations in the Spitzer Survey of Stellar Structure in Galaxies (S4G). ApJ, 753, 43.
• Graham, A.W., Spitler, L.R.; Forbes, D.A.; Lisker, T.; Moore, B.; Janz, J. (2012) : LEDA 074886: A Remarkable Rectangular-looking Galaxy. ApJ, 750, 121.
• Meidt, S.E., Schinnerer, E., Muñoz-Mateos, J.-C., Holwerda, B., Ho, L.C., Madore, B.F., K, J.H., Bosma, A, Athanassoula, E., Hinz, J.L. and 12 coauthors (2012) The S4G Perspective on Circumstellar Dust Extinction of Asymptotic Giant Branch Stars in M100. ApJL, 748, L30
• Janz J., Laurikainen E. ,, Lisker T., Salo H. , Peletier R.F., Niemi S.M., den Brok M., Toloba E., Falcon-Barroso J., Boselli A., Hensler G. (2012): Dissecting early-type dwarf galaxies into their multiple components, ApJL, 745, L24
• Meidt S. E., Schinnerer E., Knapen J.H., Bosma A., Athanassoula E., Sheth K., Buta R.J., Zaritsky D., , Laurikainen E. ,, Elmegreen D., and 16 coauthors, (2012): Reconstructing the stellar mass distributions of galaxies using S4G IRAC 3.6 and 4.5 micron images: I. Correcting for contamination by PAH, hot dust, and intermediate age stars, ApJ 744, 17
• Laurikainen E., Salo H. , Buta R., Knapen J.H (2012): Overview of the Near-IR S0 galaxy Survey (NIRS0S), Advances in Astronomy, vol. 2011, id. 516739 (astro-ph 1111.6447) Appeared in 1/2012.

  2011:

• Laurikainen E., H. Salo, R. Buta, J. H. Knapen (2011): Near-IR Atlas of S0-Sa galaxies (NIRS0S), Mon. Not. R. Astron. Soc. 418, 1452-1490.
• Elmegreen D.M., B.G. Elmegreen, A. Yau, E. Athanassoula, A. Bosma, R.J. Buta, G. Helou, L.C. Ho, D.A. Gadotti, J.H. Knapen, E. Laurikainen, B.F. Madore, K.L. Masters, S.E. Meidt, K. Menéndez-Delmestre, M.W. Regan, H. Salo, K. Sheth, D. Zaritsky, M. Aravena, R. Skibba, J.L. Hinz, J. Laine , A. Gil de Paz, J.-C. Muñoz-Mateos, M. Seibert, T. Mizusawa, T. Kim, Taehyun, S. Erroz Ferrer (2011): Grand Design and Flocculent Spirals in the Spitzer Survey of Stellar Structure in Galaxies (S4G), Astrophys. J., 737, 32 (17pp), 2011 [doi]
• Comerón S., B.G. Elmegreen, J.H. Knapen, H. Salo, E. Laurikainen, J. Laine, E. Athanassoula, A. Bosma, K. Sheth, M.W. Regan, J.L. Hinz, A. Gil de Paz, K. Menéndez-Delmestre, T. Mizusawa, J.-C. Muñoz-Mateos, M. Seibert, T. Kim, D.M. Elmegreen, D.A. Gadotti, L.C. Ho, B.W. Holwerda, J. Lappalainen, E. Schinnerer, R. Skibba (2011): Thick disks of edge-on galaxies seen through the Spitzer Survey of Stellar Structure in Galaxies (S4G): Lair of missing baryons?, Astrophys. J. ,741, 28.
• Weinmann S.M., T. Lisker, Q. Guo, H.T. Meyern, J. Janz : Dwarf galaxy populations in present-day galaxy clusters - I. Abundances and red fractions, Mon. Not. R. Astron. Soc. , 416, 1197-1214, 2011 [doi]
• Comerón S., B.G. Elmegreen, J.H. Knapen, K. Sheth, J.L. Hinz, M.W. Regan, A. Gil de Paz, J.-C. Muñoz-Mateos, K. Menéndez-Delmestre, M. Seibert, T. Kim, T. Mizusawa, E. Laurikainen,H. Salo, J. Laine, E. Athanassoula, A. Bosma, R.J. Buta, D.A. Gadotti, L.C. Ho, B. Holwerda, E. Schinnerer, D. Zaritsky: (2011) The unusual vertical mass distribution of NGC 4013 seen through the Spitzer Survey of Stellar Structure in Galaxies (S4G), Astrophys. J. Letters , 738, L17
• Melnik A.M. , P. Rautiainen : Two-component outer ring and the Galactic spiral structure, Mon. Not. R. Astron. Soc., in press, 2011 [doi] >>
• Comerón S., J.H. Knapen, K. Sheth, M.W. Regan, J.L. Hinz, A. Gil de Paz, K. Menendez-Delmestre, J.-C. Munoz-Mateos, M. Seibert,T. Kim, E. Athanassoula, A. Bosma, R.J. Buta, B.G. Elmegreen, L.C. Ho, B.W. Holwerda, E. Laurikainen, H. Salo, E. Schinnerer: (2011): The thick disk in the galaxy NGC 4244 from S4G imaging, Astrophys. J. , 729, 18(12pp)-
• Salo, H. (2011): : Twisted Disks, Science , 332, 672-673.

  2010:

• R. Buta, E. Laurikainen, H. Salo , and J. H. Knapen: Decreased Frequency of Strong Bars in S0 Galaxies: Evidence for Secular Evolution? Astrophysical Journal 721, 259-266
• Morishima, R., Spilker, L, Salo, H. , Ohtuski, K., Altobelli, N., Pilortz S.: A multilayer model for thermal infrared emission of Saturn's rings II: Albedo, spins, and vertical mixing of ring particles inferred from Cassini CIRS. Icarus 210, 330-345.
• Salo, H , French, R.G. (2010) The opposition and tilt effects of Saturn's rings from HST observations, Icarus 210, 785-813.
• Rautiainen, P. , Mel´nik, A: N-body simulations in reconstruction of the kinematics of young stars in the Galaxy, , Astron. Astrophys. 519, A70 (13 pp).
• Salo, H, Laurikainen, E, Buta, R, Knapen, J. H (2010): Astrophysical Journal Letters 715, L56-L61
• Grouchy, R. D. , Buta, R. J., Salo, H., Laurikainen, E. (2010): Ring Star Formation Rates in Barred and Nonbarred Galaxies Astrophysical Journal 139, 2465-2493
• Laurikainen, E, Salo, H. , R. Buta, J. H. Knapen and S. Comeron (2010): Photometric scaling relations of lenticular and spiral galaxies, MNRAS 405, 1089-1118
• Salo, H. , Schmidt, J (2010): N-body simulation of viscous instability, Icarus 206, 390-409.
• Comeron, S, Knapen, J., Beckman, J E. Laurikainen, H. Salo , I. Martinez-Valpuesta, and R. J. Buta: AINUR: Atlas of Images of Nuclear Rings, MNRAS 402, 2462-2490
• Sheth K., M. Regan, J.L. Hinz, A. Gil de Paz, K. Menandez-Delmestre, J-C. Muoz-Mateos, M. Seibert, T. Kim, E. Laurikainen, H. Salo, D.A. Gadotti, J. Laine, T. Mizusawa, L. Armus, E. Athanassoula, A. Bosma, R.J. Buta, P. Capak, T.H. Jarrett, D.M. Elmegreen, B.G. Elmegreen, J.H. Knapen, J. Koda, G. Helou, L.C. Ho, B.F. Madore, K.L. Masters, B. Mobasher, P. Ogle, C.Y. Peng, E. Schinnerer, J.A. Surace, D. Zaritsky, S. Comern, B. de Swardt, S.E. Meidt,M. Kasliwal, M. Aravena: "The Spitzer Survey of Stellar Structure in Galaxies (S4G)", Publ. Astron. Soc. Pac. , 122, 1397-1414
• Ronald J. Buta, Kartik Sheth, Michael Regan, Joannah L. Hinz, Armando Gil de Paz, Karin Menandez-Delmestre, Juan-Carlos Munoz-Mateos, Mark Seibert, Eija Laurikainen, Heikki Salo , Dimitri A. Gadotti, E. Athanassoula, Albert Bosma, Johan H. Knapen, Luis C. Ho, Barry F. Madore, Debra M. Elmegreen, Karen L. Masters, Sebastien Comeron, Manuel Aravena: "Mid-Infrared Galaxy Morphology from the Spitzer Survey of Stellar Structure in Galaxies (S4G): The Imprint of the de Vaucouleurs Revised Hubble-Sandage Classification System at 3.6 microns" Astrohysical Journal Supplement Series. 190, 147-165,
• Paudel S., Lisker T., Janz, J. 2010, ApJ , 724, 64

  2009:

• Schmidt, Jürgen, Ohtsuki, Keiji, Rappaport, Nicole, Salo, Heikki , Spahn, Frank (2009): Dynamics of Saturn's Dense Rings. in Saturn from Cassini-Huygens, by Dougherty, Michele K., Esposito, Larry W., Krimigis, Stamatios M., ISBN 978-1-4020-9216-9. Springer Science+Business Media B.V., 2009, p. 413
• Buta, R., Knapen, J., Elemegreen, B., Salo, H., Laurikainen, E., D. Elemegreen, I. Puerari, Block, D.(2009) : Do Bars Drive Spiral Density Waves? Astrophysical Journal 137, 4487-4516.
• Melnik A., P. Rautiainen (2009): Kinematics of the outer pseudorings and the spiral structure of the Galaxy, Astronomy Letters, 9, 609-624.
• Morishima, R., Salo, H., Ohtsuki, K.( 2009): A Multilayer Model for Thermal Infrared Emission of Saturn's Rings: Basic formulation and implications for Earth-based observations. Icarus 01, 634-654.
• Marty, B. et al. (49 coathors, including Salo, H.) (2009): Kronos: exploring the depths of Saturn with probes and remote sensing through an international mission. Experimental Astronomy, 23, 947-976 (see also erratum 977-980).
• Laurikainen, E, Salo, H , Buta, R. Knapen, J (2009): Bars, ovals, and lenses in early-type galaxies - probes of galaxy evolution. Astrophysical Journal Letters 692, L34-L39
• Treuthardt, P, Salo, H , Buta, R (2009) Dynamical Simulations of NGC 2523 and NGC 4245. Astronomical Journal , 137. 19-33.

  2008:

• Grouchy, R. D., Buta, R, Salo, H, Laurikainen, E.,Speltincx, T. (2008): Counter-Winding Spiral Structure in ESO 297-27 Astronomical Journal , 136, 980-993
• Das, M., Laurikainen, E., Salo, H., Buta, R. (2008): Variation of Bar Strength with Central Velocity Dispersion in Spiral Galaxies Astrophys. Space Sci. 137. 163-168.
• Rautiainen, P., Salo H., Laurikainen E. (2008): Model-based patterns speed estimates for 38 barred galaxies MNRAS 388, 1803-1818
• Treuthardt, P., Salo, H, Rautiainen, P. , Buta, R. (2008) : The Bar Pattern Speed of NGC 1433 Estimated Via Sticky-Particle Simulations. Astronomical Journal Astronomical Journal, 136, 300-311 .
• Speltincx, T., Laurikainen E., Salo, H. (2008) : Comparison of bar strengths in optical and near-infrared for the OSUBSGS sample . MNRAS 383, 317-329

  2007:

• Sremcevic, M., Schmidt, J., Salo, H., Seiss, M., Spahn, F., Albers, N. (2007): A Moonlet Belt in Saturn's A ring. Nature 449, 1019-1021.
  +Supplementary online material
• Laurikainen, E., Salo, H., Buta, R.\& Knapen, J. /2007) : Properties of bars and bulges in the Hubble sequence. MNRAS 381, 401-417.
• Treuthardt, P, Buta, R, Salo, H \& Laurikainen, E. (2007) . The Kinematically Measured Pattern Speeds of NGC 2523 and NGC 4245. Astron. J. 134: 1195 - 2005.
• French, R. G., Verbischer, A., Salo, H., McGhee, C., Dones, L. (2007) . Saturn's rings at true opposition. PASP 119: 623-642
• French, R. G., Salo, H., McGhee, C \& Dones, L. (2007) : Hubble Space Telescope observations of azimuthal asymmetry in Saturn's Rings. Icarus 189, 493-522.
• Hedman, M., Nicholson, P., Salo, H., Wallis, B., Buratti, B, Baines, K., Brown, R., Clark, R. (2007): Self-Gravity wake structures in Saturn's A ring revealed by Cassini-VIMS. Astron. J. 133:2624-2629.
• Karjalainen, R (2007) : Aggregate impacts in Saturn's rings Icarus 189, 523-537.
• Fuentes-Carrera, I. Rosado, M. Amram, P. Salo, H., Laurikainen, E. (2007) : Kinematics and dynamics of the M51-type galaxy pair NGC 3893/96 (KPG 302). Astron. Astrophys. 466, 847-854.

  2006:

• Laurikainen, E., Salo, H. , Buta, R, Knapen, J. H., Speltincx, T., Block, D. L. (2006) : The Near-Infrared S0 Survey. III. Morphology of 15 Southern Early-type Disk Galaxies. Astron. Journal 132, 2634-2652.
• Villata, M. .... Laurikainen, E. .. (78 authors) (2006): The unprecedented optical outburst of the quasar 3C 454.3. The WEBT campaign of 2004-2005 Astrophys. Journal 817-822
• Morishima, R., Salo, H. (2006): Simulations of dense planetary rings: IV Rotating self-gravitating particles with size distribution. Icarus 181, 272-291.
• Buta, R., Laurikainen, E., Salo, H. , Block, D. L., Knapen, J. H. (2006) : The Near-Infrared S0 Survey. II. Fourier Dissection of Early-Type Galaxy Bars. Astron. Journal 132, 1859-1876.

  2005:

• McGhee, C., French,R.C., Dones, L., Cuzzi, J.N., Salo., H. , Danos, R (2005) : HST observations of spokes in Saturn's B ring. Icarus 173, 508-521.
• Buta, R., Vasylyev, S., Salo, H., Laurikainen, E. (2005) : The distribution of bar and spiral arm strengths in disk galaxies. Astronomical Journal 130, 506-523.
• Seiss, M., Spahn, F., Sremcevic, M., Salo, H. (2005) : Structures induced by small moonlets in Saturn's rings: Implications for the Cassini Mission. Geophysical Research Letters 32, L11205(1-4).
• Nicholson, P.D., French, R.G., Campbell, D.B., Margot, J.-L., Nolan, M.C., Black, G.J., Salo, H. (2005): Radar imaging of Saturn's rings. Icarus 177, 32-62.
• Laurikainen, E., Salo, H. , Buta, R. (2005) : Multicomponent decomposition for a sample of S0 galaxies. MNRAS . 362, 1319-1347.
• Rautiainen, P, Salo, H., Laurikainen, E. (2005) : The pattern speeds of 38 galaxies. Astrophys. Journal 631, L129-L132. .

  2004:

• Buta, R, Laurikainen, E., Salo, H (2004): The distribution of maximum relative gravitational torque in disk galaxies. Astron. J 127, 279-294.
• Fuentes-Carrera, I, Rosado, M, Amram, P., Dultzin-Hacyan, D. Cruz-Conzales, I, Salo, H, Laurikainen, E, Bernal, A, Ambrocio-Cruz, P, Le Coarer, E (2004): The isolated interacting galaxy pair NGC 5426/27 (Arp 271). Astron. Astrophys. 415, 451-469
• Rautiainen, P., Salo, H., Buta, R. (2004): Dynamical modelling of a remarkable four-armed barred spiral galaxy ESO 566-24. MNRAS 349, 933-944.
• Morishima, R, Salo., H (2004): Spin rates of small moonlets embedded in planetary rings: I. Three body calculations. Icarus 167, 330-346
• Morishima, R, Watanabe, S. (2004): Co-accretion of the Earth-Moon system after the giant impact: reduction of the total angular momentum by lunar impact ejecta. Icarus 168, 60-79
• Laurikainen, E., Salo, H., Buta, R. (2004): Comparison of bar strengths and fraction of bars in active and non-active galaxies. Astrophys. J 607, 103-124.
• Salo, H., Karjalainen, R., French, R.G (2004): Photometric modeling of Saturn's rings: II. Azimuthal asymmetry in reflected and transmitted ligth. Icarus 170, 70-90.
• Karjalainen, R., Salo, H (2004): Gravitational accretion of particles in Saturn's rings. Icarus 172, 328-348.
• Laurikainen, E., Salo, H., Buta, R., Vasylyev, S. (2004): Bar-induced perturbations strengths of the galaxies in the Ohio State University Bright Galaxy Survey (OSUBGS). MNRAS 355, 1251-1271.

  2003:

• Schmidt, J, Salo, H. (2003) : A weakly nonlinear model for oscillatory instability in Saturn's dense rings. Phys. Rev. Lett 90, 061102-1 - 061102-4
• Bergvall N., Laurikainen E., Aalto S. (2003): Galaxy interactions - poor starburst triggers: A study of a complete sample of interacting galaxies. III. Astron. Astrophys. 405, 31-52.
• Salo, H, Karjalainen, R (2003): Photometric modeling of Saturn's rings: I. Monte Carlo method and the effect of non-zero volume filling factor. Icarus 164, 428-460.

  2002:

• Laurikainen, E, Salo, H. & Rautiainen, P.(2002): Comparison of bar strengths in active and non-axtive galaxies. MNRAS , 331, 880-893
• Rautiainen, P., Salo, H & Laurikainen, (2002) : Simulations of central structure in barred galaxies. MNRAS 337, 1233-1244.
• Laurikainen, E, Salo, H. (2002): Bar strengths in spiral galaxies estimated from 2MASS images. MNRAS 337, 1118-1138.

  2001:

• Laurikainen, E. & Salo, H. (2001) : BVRI Imaging of M51-type Interacting Galaxy Pairs III. Analysis of the photometric parameters. MNRAS 324, 685-698.
• Salo, H., Schmidt. J. & Spahn, F. (2001) : Viscous overstability in Saturn's B-ring: I. Direct simulations and measurement of transport coefficients. Icarus 153, 295-315.
• Schmidt. J., Salo, H., Spahn, F. & Petzschmann, O. (2001) : Viscous overstability in Saturn's B-ring: II. Hydrodynamic theory and comparison to simulations. Icarus 153, 316-331.
• Salo, H. & Laurikainen, E. (2001): N-body models of M51: From extended tail to central spiral structure. Astron. Astrophys Trans. 20, 93-101.

  2000:

• Laurikainen, E. & Salo, H. (2000): BVRI Imaging of M51-type Interacting Galaxy Pairs II. Bulge and disk parameters. Astronomy Astrophys. Suppl. 141, 103-111 (+19 pages in electronic form)
• Spahn, F., Schmidt, J., Petzschmann, O. & Salo, H. (2000): Stability analysis of a Keplerian disk of granular grains: influence of thermal diffusion. Icarus 145, 657-660.
• Rautiainen, P. & Salo, H. (2000) N-body simulations of resonance rings in galactic disks. Astron. Astrophys. 362, 465-485.
• Salo, H. & Laurikainen, E. (2000): N-body model for M51: I. Multiple encounter vs. single passage?. MNRAS 319, 377-392 .
• Salo, H. & Laurikainen, E. (2000): N-body model for M51: II. Inner structure. MNRAS 319, 393-413.

  1999:

• Moss, D., Rautiainen, P. & H. Salo (1999): A dynamo model for the magnetic field of the weakly barred galaxy IC 4214. MNRAS, 303, 125-132.
• Buta, R., Purcell, G.B., Cobb, M., Crocker, D.A., Rautiainen, P., & Salo, H. (1999): The Structure and Dynamics of the Early-Type Resonance Ring Galaxy IC 4214. I. Observations. Astron. J. 117, 778-791.
• Salo, H., Rautiainen, P., Buta, R., Purcell, G.B., Cobb, M., Crocker, D.A., & Laurikainen, E. (1999): The Structure and Dynamics of the Early-Type Resonance Ring Galaxy IC 4214. II. Models. Astron. J. 117, 792-810.
• Salo, H. & Laurikainen, E. (1999): Inner Structure of M51. Astrophys. Space Sci. 269-270, 589-592.
• Salo, H. & Laurikainen, E. (1999): A multiple encounter model of M51. Astrophysics and Space Science 269-270: 663-664.
• Schmidt, J., Salo, H., Petzshman, O. & Spahn, F. (1999): Vertical distribution of temperature and density in a planetary ring. Astron. Astrophys. 345, 646-652.
• Rautiainen, P. & Salo, H. (1999): Multiple pattern speeds in barred galaxies. Astron. Astrophys. 348, 737-754.

  1998:

• Salo, H. & Hanninen, J. (1998): Neptune's Partial Rings: Action of Galatea on Self-Gravitating Particles. Science 282, 1102-1104.
• Moss, D., Korpi, M., Rautiainen, P. & H. Salo (1998): The evolution of dynamo maintained magnetic fields in a barred spiral galaxy. Astron. Astrophys. 329, 895-905.
• Laurikainen, E. & Salo, H. & Aparacio, A. (1998): BVRI Imaging of M51-type Interacting Galaxy Pairs. Astron. Astrophys. Suppl. 129, 517-540.

Invited talks in International conferences:

• Salo, H. (1999): ``Numerical exploration of planetary ring dynamics'', 215th WE-Hereaus Conference on Granular Gases, Bad Honnef, Germany, 8-13.3.1999
• Salo, H. and Laurikainen, E. (2000): ``Simulation modelling of M51: from extended tail to inner spiral structure'', European Astronomical Society, JENAM-2000, Moscow, 29.5-4.6.2000
• Salo, H., Scmidt, J., Spahn, F (2002): ``Viscous stability properties of dense planetary rings'', Granular Gases: Theory-Experiments-Simulations Conference, CECAM, Lyon, France, 2-5.9.2002
• Salo, H. Laurikainen, E. Buta, R (2004): "Estimation of bar strengths form near-IR images", ``Penetrating Bars through Masks of Cosmic Dust'' Pilanesberg, South Africa, 7-12.2004.
• Salo, H , Schmidt J (2007): ``Dynamical and photometric modeling of dense planetary rings'', European Planetary Science Conference, Potsdam, Germany 20-24.8.2007.
• Salo, H (2009): ``Role of Self-gravity in Saturn's Rings'', European Planetary Science Conference, Potsdam, Germany 2009.
• Salo, H (2011)" Simulating the formation of fine-scale structure in Saturn's rings", Nin onequilibrium Dynamics in Astrophysics and Material Science Conference, Yukawa Institute, Kyoto Japan, 31.10-3.11.2011
• Salo, H (2012) in "Dust and grains in Low Gravity and Space Environment", ESA/ESTEC, Netherlands 2-4.2.2012
• Salo, H (2013) The 7th Korean Astrophysics workshop on Dynamics of Disk Galaxies'', Seoul 21-24.10,2013
• Salo, H (2014) Lowell workshop on Exponential disk galaxies, Arizona, to be held in Oct 2014

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