We present a study of low surface brightness galaxies(LSBGs) selected by fitting the images for all the galaxies inα.40 SDSS DR7 sample with two kinds of single-component models and two kinds of two-component models(...We present a study of low surface brightness galaxies(LSBGs) selected by fitting the images for all the galaxies inα.40 SDSS DR7 sample with two kinds of single-component models and two kinds of two-component models(disk+bulge):single exponential,single sersic,exponential+deVaucular(exp+deV),and exponential+sérsic(exp+ser).Under the criteria of the B band disk central surface brightness μ_(0,disk)(B)≥22.5 mag arcsec^(-2) and the axis ratio b/a> 0.3,we selected four none-edge-on LSBG samples from each of the models which contain 1105,1038,207,and 75 galaxies,respectively.There are 756 galaxies in common between LSBGs selected by exponential and sersic models,corresponding to 68.42% of LSBGs selected by the exponential model and 72.83% of LSBGs selected by the sersic model,the rest of the discrepancy is due to the difference in obtaining μ_(0) between the exponential and sersic models.Based on the fitting,in the range of 0.5≤n≤1.5,the relation of μ_(0) from two models can be written as μ_(0,sérsic)-μ_(0,exp)=-1.34(n-1).The LSBGs selected by disk+bulge models(LSBG_(2)comps) are more massive than LSBGs selected by single-component models(LSBG_1comp),and also show a larger disk component.Though the bulges in the majority of our LSBG_(2)comps are not prominent,more than 60% of our LSBG_(2)comps will not be selected if we adopt a single-component model only.We also identified 31 giant low surface brightness galaxies(gLSBGs) from LSBG_(2)comps.They are located at the same region in the color-magnitude diagram as other gLSBGs.After we compared different criteria of gLSBGs selection,we find that for gas-rich LSBGs,M_(*)> 10^(10)M_⊙ is the best to distinguish between gLSBGs and normal LSBGs with bulge.展开更多
This paper presents the results of Hαimaging of 169 galaxies randomly selected from the α.40-SDSS catalog.The sample has excluded all low surface brightness galaxies (LSBGs) whose central surface brightness in B ban...This paper presents the results of Hαimaging of 169 galaxies randomly selected from the α.40-SDSS catalog.The sample has excluded all low surface brightness galaxies (LSBGs) whose central surface brightness in B band (μ0(B)) fainter than 22.5 mag arcsec-2.It can be used as the counterparts sample to LSBGs.We observed their Hα and R band images by using the 2.16 m telescope at the Xinglong Observatory of the National Astronomical Observatories,Chinese Academy of Sciences (NAOC).The main goal of this work is to present the properties of those galaxies,together with Hαflux and star formation-,gas-,stellar mass-surface density.In addition,we confirm the correlations among HI content,stellar mass and star formation in ALFALFA galaxies.The HI mass increases with stellar mass,and the slope slows down at the higher stellar mass.The overall trend was that the specific star formation rate (s SFR) decreases with stellar mass,and the sSFR dropped sharply when the stellar mass is close to 1010.3~1010.5M⊙.The weak correlation between SFR/MHIand MHIimplies the HI contribute little to star formation.Our sample,which are mostly star-forming galaxies,follows the revisited Kennicutt-Schmidt law as well as the Kennicutt-Schmidt law.展开更多
基金supported by the National Key R&D Program of China (grant No.2022YFA1602901)support of the National Natural Science Foundation of China(NSFC) grant Nos. 12090040, 12090041, and 12003043+5 种基金supported by the Youth Innovation Promotion AssociationCAS (No. 2020057)the science research grants of CSST from the China Manned Space Projectsupport of the NSFC grant Nos.11733006 and U1931109supported by the Strategic Priority Research Program of the Chinese Academy of Sciences,Grant No. XDB0550100partially supported by the Open Project Program of the Key Laboratory of Optical Astronomy,National Astronomical Observatories,Chinese Academy of Sciences。
文摘We present a study of low surface brightness galaxies(LSBGs) selected by fitting the images for all the galaxies inα.40 SDSS DR7 sample with two kinds of single-component models and two kinds of two-component models(disk+bulge):single exponential,single sersic,exponential+deVaucular(exp+deV),and exponential+sérsic(exp+ser).Under the criteria of the B band disk central surface brightness μ_(0,disk)(B)≥22.5 mag arcsec^(-2) and the axis ratio b/a> 0.3,we selected four none-edge-on LSBG samples from each of the models which contain 1105,1038,207,and 75 galaxies,respectively.There are 756 galaxies in common between LSBGs selected by exponential and sersic models,corresponding to 68.42% of LSBGs selected by the exponential model and 72.83% of LSBGs selected by the sersic model,the rest of the discrepancy is due to the difference in obtaining μ_(0) between the exponential and sersic models.Based on the fitting,in the range of 0.5≤n≤1.5,the relation of μ_(0) from two models can be written as μ_(0,sérsic)-μ_(0,exp)=-1.34(n-1).The LSBGs selected by disk+bulge models(LSBG_(2)comps) are more massive than LSBGs selected by single-component models(LSBG_1comp),and also show a larger disk component.Though the bulges in the majority of our LSBG_(2)comps are not prominent,more than 60% of our LSBG_(2)comps will not be selected if we adopt a single-component model only.We also identified 31 giant low surface brightness galaxies(gLSBGs) from LSBG_(2)comps.They are located at the same region in the color-magnitude diagram as other gLSBGs.After we compared different criteria of gLSBGs selection,we find that for gas-rich LSBGs,M_(*)> 10^(10)M_⊙ is the best to distinguish between gLSBGs and normal LSBGs with bulge.
基金supported by the National Natural Science Foundation of China (Grant Nos. 12003043, 11733006, 12090041, 12090040, 12073035, 11890693 and U1931109)the National Key R&D Program of China (No. 2017YFA0402704)+2 种基金partially supported by the Open Project Program of the Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciencessupported by NSF grant AST-0607007 and AST-1107390by grants from the Brinson Foundation
文摘This paper presents the results of Hαimaging of 169 galaxies randomly selected from the α.40-SDSS catalog.The sample has excluded all low surface brightness galaxies (LSBGs) whose central surface brightness in B band (μ0(B)) fainter than 22.5 mag arcsec-2.It can be used as the counterparts sample to LSBGs.We observed their Hα and R band images by using the 2.16 m telescope at the Xinglong Observatory of the National Astronomical Observatories,Chinese Academy of Sciences (NAOC).The main goal of this work is to present the properties of those galaxies,together with Hαflux and star formation-,gas-,stellar mass-surface density.In addition,we confirm the correlations among HI content,stellar mass and star formation in ALFALFA galaxies.The HI mass increases with stellar mass,and the slope slows down at the higher stellar mass.The overall trend was that the specific star formation rate (s SFR) decreases with stellar mass,and the sSFR dropped sharply when the stellar mass is close to 1010.3~1010.5M⊙.The weak correlation between SFR/MHIand MHIimplies the HI contribute little to star formation.Our sample,which are mostly star-forming galaxies,follows the revisited Kennicutt-Schmidt law as well as the Kennicutt-Schmidt law.
