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The stellar archeology of the M33 disk: recent star-forming history and constraints on the timing of an interaction with M31

Par Conseil national de recherches du Canada

DOITrouver le DOI : https://doi.org/10.1088/0004-637X/738/2/144
AuteurRechercher : 1; Rechercher : 1
Affiliation
  1. Conseil national de recherches du Canada. Institut Herzberg d'astrophysique du CNRC
FormatTexte, Article
Sujetgalaxies: evolution; galaxies: individual (M33); galaxies: spiral
Résumé
Images recorded with MegaCam are used to investigate the recent (t ≤ 0.25 Gyr) star-forming history (SFH) of the Local Group Sc galaxy M33. The data sample the entire star-forming disk, as well as areas immediately to the north and south of the galaxy. The properties of the stellar disk change near R GC = 8 kpc. Within this radius the luminosity function of main-sequence stars indicates that the star formation rate (SFR) has been constant with time during at least the past 250 Myr, while at larger radii the SFR has declined during this same time period. That the recent SFR in the inner disk has been constant suggests that M33 has evolved in isolation for at least the past ~0.5 Gyr, thereby providing a constraint on the timing of any recent interaction with M31. The color of the main-sequence ridgeline changes with radius, suggesting a gradient in extinction of size ΔAV /ΔR GC = –0.05 mag kpc⁻¹. The fractional contribution that young stars make to the total mass of the stellar disk changes with radius, peaking near 8 kpc. Evidence is also presented of systematic spatial variations in the SFH of the disk, such that the SFR during the past 100 Myr in the southern half of the galaxy has been ~0.4 dex higher than in the northern half. Finally, structures with sizes spanning many kpc that contain blue objects—presumably main-sequence stars that formed during intermediate epochs—are identified near the disk boundary. It is argued that these are tidal features that were pulled from the main body of M33 and—in some cases—are the fossil remnants of star formation that occurred in an extended disk during intermediate epochs.
Date de publication
Maison d’éditionAmerican Astronomical Society
IOP Publishing
Dans
  • The Astrophysical Journal 738, nº 2 : 144-1–144-23.
Langueanglais
Publications évaluées par des pairsOui
Numéro NPARC19709163
Exporter la noticeExporter en format RIS
Signaler une correctionSignaler une correction (s'ouvre dans un nouvel onglet)
Identificateur de l’enregistrement57c70c16-4ee0-4bef-97d1-88659c5a24f7
Enregistrement créé2012-03-23
Enregistrement modifié2020-04-21
Date de modification :