The Relationship Between Recent and Old Star Formation in Dwarf Irregular Galaxies

Document Type : Research Paper

Authors

Department of Physics, Sharif University of Technology, Tehran, Iran

10.22128/ijaa.2026.3206.1242

Abstract

In this paper, we investigate the structural properties of local dwarf irregular galaxies, including optical scale lengths, position angles, and star formation rates, using data from the LITTLE THINGS survey. Our analysis is based on a sample of 24 dwarf irregular galaxies. Optical structural parameters are derived from $B$ and $V$ band images, while recent star formation rates are estimated using $H_{\alpha}$ data. Our goal is to identify correlations among properties associated with the same epoch, such as relationships between scale lengths measured in different optical bands, as well as to explore connections between different evolutionary stages. In particular, we examine how recent star formation relates to the $B-V$ color index, V-band luminosity and magnitude, and scale lengths as measured in optical wavelengths. We find that (A) there is a strong correlation between scale lengths measured in different optical bands and (B) Recent star formation rates show strong correlations with both galaxy magnitude and scale length in the visible filter, indicating that very recent star formation activity (on timescales of $\sim$1 Myr) is closely linked to older star formation activity (on timescales of $\sim$1 Gyr). The results for our sample are consistent and in good agreement with values reported in literature. 

Keywords

References

[1] Hunter, D. A., Ficut-Vicas, D., Ashley, T., et al. 2012, AJ, 144, 134.
[2] Hunter, D. A., & Elmegreen, B. G. 2004, AJ, 128, 2170.
[3] Hunter, D. A., & Elmegreen, B. G. 2006, ApJS, 162, 49.
[4] Leroy, A. K., Bigiel, F., de Blok, W. J. G., Bolatto, A. D., Brinks, E., Madore, B., & Murphy, E. 2012, AJ, 144, 3.
[5] de Vaucouleurs, G. 1959, in Handbuch der Physik, 53, 275.
[6] de Vaucouleurs, G., de Vaucouleurs, A., Corwin, H. G., Buta, R. J., Paturel, G., & Fouqué, P. 1991, Third Reference Catalogue of Bright Galaxies (New York: Springer) (RC3).
[7] Holmberg, E. 1958, Meddelanden från Lunds Astronomiska Observatorium, Ser. II, 136, 1.
[8] de Vaucouleurs, G., de Vaucouleurs, A., & Corwin, H. G. 1976, Second Reference Catalogue of Bright Galaxies (Austin: Univ. Texas Press) (RC2).
[9] Freeman, K. C. 1970, ApJ, 160, 811.
[10] de Jong, R. S. 1996, A&AS, 118, 557.
[11] Caldwell, N., & Bothun, G. D. 1987, AJ, 94, 1126.
[12] Impey, C., Bothun, G., & Malin, D. 1988, ApJ, 330, 634.
[13] Kennicutt, R. C., Jr. 1998, ARA&A, 36, 189.
[14] Rosenfeld, A., & Kak, A. C. 1976, Digital Picture Processing (New York: Academic Press).
[15] Lee, J. S. 1980, IEEE Trans. Pattern Anal. Mach. Intell., 2, 165.
[16] Sharma, A., Bhateja, V., & Tripathi, A. 2016, in Information Systems Design and Intelligent Applications, ed. S. C. Satapathy et al., Advances in Intelligent Systems and Computing, Vol. 434 (New Delhi: Springer), 663.
[17] Buades, A., Coll, B., & Morel, J.-M. 2005, in Proc. IEEE Comput. Soc. Conf. Comput. Vis. Pattern Recognit. (CVPR), 2, 60.
[18] Efron, B. 1979, Ann. Statist., 7, 1.
[19] Cardelli, J. A., Clayton, G. C., & Mathis, J. S. 1989, ApJ, 345, 245.
[20] Kennicutt, R. C., Jr. 1998, ARA&A, 36, 189.
[21] Murphy, E. J., Condon, J. J., Schinnerer, E., Kennicutt, R. C., Calzetti, D., Armus, L., et al. 2011, ApJ, 737, 67.
[22] Hao, C.-N., Kennicutt, R. C., Jr., Johnson, B. D., Dale, D. A., Calzetti, D., Moustakas, J., et al. 2011, ApJ, 741, 124.
[23] Salpeter, E. E. 1955, ApJ, 121, 161.
[24] Kroupa, P. 2001, MNRAS, 322, 231.
[25] Karachentsev, I. D., Kaisin, S. S . 2013, AJ, 146, 46.
[26] Afanasiev, V. L., & Moiseev, A. V., 2005, Astronomy Letters, 31, 194.
[27] Karachentsev, I. D., Kaisin, S. S., 2010, AJ, 140, 1241. 
Iranian Journal of Astronomy and Astrophysics
Volume 12, Issue 3
December 2025
Pages 249-266

Files

Share

How to cite

Statistics