The Panchromatic Hubble Andromeda Treasury: Triangulum Extended Region (PHATTER). II. The Spatially Resolved Recent Star Formation History of M33
The Panchromatic Hubble Andromeda Treasury: Triangulum Extended Region (PHATTER). II. The Spatially Resolved Recent Star Formation History of M33
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DOI：
10.3847/1538-4357/ac7568
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发表时间：
2022-06
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通讯作者：
M. Lazzarini;B. Williams;M. Durbin;J. Dalcanton;A. Smercina;E. Bell;Yumi Choi;A. Dolphin;K. Gilbert;P. Guhathakurta;E. Rosolowsky;E. Skillman;O. Telford;D. Weisz
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作者：
M. Lazzarini;B. Williams;M. Durbin;J. Dalcanton;A. Smercina;E. Bell;Yumi Choi;A. Dolphin;K. Gilbert;P. Guhathakurta;E. Rosolowsky;E. Skillman;O. Telford;D. Weisz
我们使用哈勃太空望远镜拍摄的光学图像来测量 M33 的空间分辨近期恒星形成历史 (SFH)，作为全色哈勃仙女座宝库：三角延伸区域 (PHATTER) 调查的一部分。本分析中使用的观测覆盖的区域覆盖了约 38 kpc2 的去投影区域，并沿长轴和半长轴分别从 M33 中心延伸至约 3.5 和约 2 kpc。我们将 PHATTER 光学勘测划分为 2005 个区域，每侧测量 24 角秒、∼100 pc，并分别为每个区域拟合颜色-幅度图，以测量 PHATTER 足迹内 M33 的空间分辨率 SFH。 SFH 在小空间尺度以及我们测量到大约 630 Myr 之前的整个星系范围内都有显着的波动。我们在年龄小于 80 Myr 的恒星族中观察到更加絮状的螺旋结构，而较老的恒星族的结构则以两个旋臂为主。我们还观察到 M33 中心有一家酒吧，该酒吧在年龄超过 80 马币的人群中占主导地位。最后，我们发现 PHATTER 足迹内过去 100 Myr 的平均恒星形成率 (SFR) 为 0.32 ± 0.02 M⊙ yr−1。我们测得当前的 SFR（过去 10 Myr）为 0.20 ± 0.03 M⊙ yr−1。当按比例缩放以考虑 PHATTER 勘测足迹覆盖的 D25 区域的一部分时，该恒星形成率略高于之前的宽带估计测量值。
We measure the spatially resolved recent star formation history (SFH) of M33 using optical images taken with the Hubble Space Telescope as part of the Panchromatic Hubble Andromeda Treasury: Triangulum Extended Region (PHATTER) survey. The area covered by the observations used in this analysis covers a de-projected area of ∼38 kpc2 and extends to ∼3.5 and ∼2 kpc from the center of M33 along the major and semimajor axes, respectively. We divide the PHATTER optical survey into 2005 regions that measure 24 arcsec, ∼100 pc, on a side and fit color–magnitude diagrams for each region individually to measure the spatially resolved SFH of M33 within the PHATTER footprint. There are significant fluctuations in the SFH on small spatial scales and also galaxy-wide scales that we measure back to about 630 Myr ago. We observe a more flocculent spiral structure in stellar populations younger than about 80 Myr, while the structure of the older stellar populations is dominated by two spiral arms. We also observe a bar in the center of M33, which dominates at ages older than about 80 Myr. Finally, we find that the mean star formation rate (SFR) over the last 100 Myr within the PHATTER footprint is 0.32 ± 0.02 M⊙ yr−1. We measure a current SFR (over the last 10 Myr) of 0.20 ± 0.03 M⊙ yr−1. This SFR is slightly higher than previous measurements from broadband estimates, when scaled to account for the fraction of the D25 area covered by the PHATTER survey footprint.