Interaction effects on galaxy pairs with Gemini/GMOS-I: Electron density

Author(s)

Krabbe, A. C. ^[1] ; Rosa, D. A. ^[1] ; Dors, Jr., O. L. ^[1] ; Pastoriza, M. G. ^[2] ; Winge, C. ^[3] ; Haegele, G. F. ^{[4, 5]} ; Cardaci, M. V. ^{[4, 5]} ; Rodrigues, I. ^[1]

Affiliation

^[1] Univ Vale Paraiba, BR-12244000 Sao Jose Dos Campos, SP - Brazil

^[2] Univ Fed Rio Grande do Sul, Inst Fis, BR-91359050 Porto Alegre, RS - Brazil

^[3] AURA Inc, Gemini Observ, La Serena - Chile

^[4] CONICET La Plata UNLP, Inst Astrofis La Plata, La Plata, Buenos Aires - Argentina

^[5] Univ Nacl La Plata, Fac Ciencias Astron & Geofis, RA-1900 La Plata - Argentina

• Document type: Journal article
• Source: Monthly Notices of the Royal Astronomical Society; v. 437, n. 2, p. 1155-1170, JAN 2014.
• Web of Science Citations: 17

Abstract

We present an observational study about the impacts of the interactions on the electron density of H II regions located in seven systems of interacting galaxies. The data consist of long-slit spectra in the range 4400-7300 angstrom, obtained with the Gemini Multi-Object Spectrograph at Gemini South (GMOS-S). The electron density was determined using the ratio of emission lines {[}S II] lambda 6716/lambda 6731. Our results indicate that the electron density estimates obtained of H II regions from our sample of interacting galaxies are systematically higher than those derived for isolated galaxies. The mean electron density values of interacting galaxies are in the range of N-e = 24-532 cm(-3), while those obtained for isolated galaxies are in the range of N-e = 40-137 cm(-3). Comparing the observed emission lines with predictions of photoionization models, we verified that almost all the H II regions of the galaxies AM 1054A, AM 2058B and AM 2306B have emission lines excited by shock gas. For the remaining galaxies, only few H II regions have emission lines excited by shocks, such as in AM 2322B (one point) and AM 2322A (four points). No correlation is obtained between the presence of shocks and electron densities. Indeed, the highest electron density values found in our sample do not belong to the objects with gas shock excitation. We emphasize the importance of considering these quantities especially when the metallicity is derived for these types of systems. (AU)

• FAPESP's process: 11/08202-6 - Interaction effects on the chemical evolution and stellar population of interacting galaxies
• Grantee: Deise Aparecida Rosa
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 10/01490-3 - Interacting galaxies: effects in the stellar population and the physical properties of the ionized gas
• Grantee: Angela Cristina Krabbe
• Support Opportunities: Research Grants - Young Investigators Grants
• FAPESP's process: 09/14787-7 - Physical properties of star formation regions in circumnuclear rings and in (U)LIRGs
• Grantee: Oli Luiz Dors Junior
• Support Opportunities: Research Grants - Young Investigators Grants