The DIRECT project aims to determine direct distances to two important galaxies in the cosmological distance ladder – M31 and M33 – using detached eclipsing binaries (DEBs) and Cepheids. The search for these variables requires time-series photometry of large areas of the target galaxies and yields magnitudes and positions for tens of thousands of stellar objects, which may be of use to the astr...

We present a catalog of 4780 extended sources from the outer field of M33. The catalog includes 73 previously identified clusters or planetary nebulae, 1153 likely background galaxies, and 3554 new candidate stellar clusters. The survey is based on deep ground-based images obtained with the MegaCam instrument on the CFHT telescope. We provide gri photometry for detected objects as well as estim...

In this paper we investigate the X-ray spectra and X-ray spectral variability of compact X-ray sources for 3 Chandra observations of the Local Group galaxy M33. The observations are centered on the nucleus and the star forming region NGC 604. In the observations 261 sources have been detected. For a total of 43 sources the number of net counts is above 100, sufficient for a more detailed spectr...

We present a new determination of the metallicity gradient in M33, based on Keck/LRIS measurements of oxygen abundances using the temperature-sensitive emission line [O III] λ4363 Å in 61 H II regions. These data approximately triple the sample of direct oxygen abundances in M33. We find a central abundance of 12 + log(O/H) = 8.36±0.04 and a slope of −0.027±0.012 dex kpc−1, in agreement with in...

We show with a short Chandra HRC-S exposure that the powerful X-ray source coincident with the nucleus of M33 is unresolved at the highest spatial resolution available to date (0. ′′ 4). The source flux is variable, doubling during the 5 ks exposure. The combination of properties exhibited by M33 X-8 establishes the source as the nearest example of the ultra-luminous X-ray sources that have bee...

We propose a technique to test the idea that non-standard dynamics, rather than dark matter halos, might be responsible for the observed rotation curves of spiral galaxies. In the absence of non-luminous matter, a galactic disk’s rotational velocity and its vertical velocity dispersion can be used jointly to test the self-consistency of the galaxy’s dynamics. A specific illustrative example, us...

سابقه و هدف: امروزه با گسترش فعالیت واحدهای صنعتی، غلظت آلاینده­ ها در هوا افزایش یافته انسان­ از طریق تنفس، بلعیدن جذب پوستی معرض آن­ها قرار می­ گیرند. میان تمام آلاینده ­ها، فلزات سنگین به دلیل ماهیت سمی خود بسیار مورد توجه متخصصان زیست ­محیطی گرفته ­اند. بالای محیط ­زیست، می ­تواند خطر اثرات نامطلوب بر سلامتی انسان را دهد. شهرک صنعتی ناجی زنجان ریخته ­گری مس آلیاژهای آن، ­عنوان یکی منابع انت...

We report deep imaging observations with DOLoRes@TNG of an ultra-faint dwarf satellite candidate the Triangulum galaxy (M33) found by visual inspection public data release DESI Legacy Imaging Surveys. Pisces VII/Triangulum (Tri) III is at a projected distance 72 kpc from M33, and using tip red giant branch method we estimate D=1.0 +0.3,-0.2 Mpc, meaning could either be isolated or second known ...