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Revisiting the Extended Schmidt Law: The Important Role of Existing Stars in Regulating Star Formation

Shi, Yong and Yan, Lin and Armus, Lee and Gu, Qiusheng and Helou, George and Qiu, Keping and Gwyn, Stephen and Stierwalt, Sabrina and Fang, Min and Chen, Yanmei and Zhou, Luwenjia and Wu, Jingwen and Zheng, Xianzhong and Zhang, Zhi-Yu and Gao, Yu and Wang, Junzhi (2018) Revisiting the Extended Schmidt Law: The Important Role of Existing Stars in Regulating Star Formation. Astrophysical Journal, 853 (2). Art. No. 149. ISSN 1538-4357.

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We revisit the proposed extended Schmidt law, which posits that the star formation efficiency in galaxies depends on the stellar mass surface density, by investigating spatially resolved star formation rates (SFRs), gas masses, and stellar masses of star formation regions in a vast range of galactic environments, from the outer disks of dwarf galaxies, to spiral disks and to merging galaxies, as well as individual molecular clouds in M33. We find that these regions are distributed in a tight power law as Σ _SFR ∝ (Σ_(star)^0.5 Σ__gas)^(1.09), which is also valid for the integrated measurements of disk and merging galaxies at high-z. Interestingly, we show that star formation regions in the outer disks of dwarf galaxies with Σ_(SFR) down to 10^(−5) M_ ⊙ yr^(−1) kpc^(−2), which are outliers of both the Kennicutt–Schmidt and Silk–Elmegreen laws, also follow the extended Schmidt law. Other outliers in the Kennicutt–Schmidt law, such as extremely metal-poor star formation regions, also show significantly reduced deviation from the extended Schmidt law. These results suggest an important role for existing stars in helping to regulate star formation through the effect of their gravity on the midplane pressure in a wide range of galactic environments.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Shi, Yong0000-0002-8614-6275
Yan, Lin0000-0003-1710-9339
Gu, Qiusheng0000-0002-3890-3729
Qiu, Keping0000-0002-5093-5088
Stierwalt, Sabrina0000-0002-2596-8531
Fang, Min0000-0001-8060-1321
Wu, Jingwen0000-0001-7808-3756
Zheng, Xianzhong0000-0003-3728-9912
Zhang, Zhi-Yu0000-0002-7299-2876
Gao, Yu0000-0003-0007-2197
Additional Information:© 2018 American Astronomical Society. Received 2017 August 8. Accepted 2017 December 19. Published 2018 February 1. We thank the anonymous referee for the helpful and constructive suggestions that improved the quality of the paper, Eve Ostriker for discussions of their model and Pereira-Santaella for providing their measurements of SFRs and gas mass of IC 4687. The work is supported by the National Key R&D Program of China (No. 2017YFA0402704) and the National Natural Science Foundation of China (NSFC grants 11773013, 11733002, and 11373021) and the Excellent Youth Foundation of the Jiangsu Scientific Committee (BK20150014). K.Q. acknowledges the support from NSFC (11473011 and 11590781). This work is based on observations obtained at the Canada–France–Hawaii Telescope (CFHT), which is operated by the National Research Council of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique of France, and the University of Hawaii. The GALEX is a NASA Small Explorer. The mission was developed in cooperation with the Centre National d'Etudes Spatiales of France and the Korean Ministry of Science and Technology. This work is based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the data archive at the Space Telescope Science Institute. STScI is operated by the Association of Universities for Research in Astronomy, Inc. under NASA contract NAS 5-26555. This paper makes use of the following ALMA data: ADS/JAO.ALMA#2011.0.00182.S. ALMA is a partnership of ESO (representing its member states), NSF (USA) and NINS (Japan), together with NRC (Canada), NSC and ASIAA (Taiwan), and KASI (Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO, and NAOJ. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. The Submillimeter Array is a joint project between the Smithsonian Astrophysical Observatory and the Academia Sinica Institute of Astronomy and Astrophysics and is funded by the Smithsonian Institution and the Academia Sinica. This research has made use of the NASA/IPAC Extra-galactic Database (NED), which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
China National R&D Program2017YFA0402704
National Natural Science Foundation of China11773013
National Natural Science Foundation of China11733002
National Natural Science Foundation of China11373021
Jiangsu Scientific Committee Excellent Youth Foundation BK20150014
National Natural Science Foundation of China11473011
National Natural Science Foundation of China11590781
NASANAS 5-26555
Smithsonian InstitutionUNSPECIFIED
Academia SinicaUNSPECIFIED
Subject Keywords:galaxies: evolution; galaxies: starburst; ISM: atoms; ISM: molecules; stars: formation
Record Number:CaltechAUTHORS:20180202-082630507
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Official Citation:Yong Shi et al 2018 ApJ 853 149
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:84645
Deposited By: Ruth Sustaita
Deposited On:02 Feb 2018 17:10
Last Modified:02 Feb 2018 17:10

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