We present a progress report of a project to study the quantitative star
formation history (SFH) in different parts of the Small Magellanic Cloud (SMC).
We use the information in (B-R), R ...color-magnitude diagrams (CMDs), which
reach down to the oldest main-sequence turnoffs and allow us to retrieve the
SFH in detail. We show the first results of the SFH in a SMC field located in
the Southern direction (at $\thicksim$1 kpc from the SMC center). This field is
particularly interesting because in spite of being located in a place in which
the HI column density is very low, it still presents a recent enhancement of
star formation.
We present the discovery of a very faint stellar system, SMASH 1, that is potentially a satellite of the Large Magellanic Cloud. Found within the Survey of the MAgellanic Stellar History (SMASH), ...SMASH 1 is a compact (r(h) 9.1(-3.4)(+5.9)pc) and very low luminosity (M-V = -1.0 +/- 0.9, L-V = 10(2.3 +/- 0.4) L-circle dot) stellar system that is revealed by its sparsely populated main sequence and a handful of red giant branch candidate member stars. The photometric properties of these stars are compatible with a metal-poor (Fe/H = -2.2) and old (13 Gyr) isochrone located at a distance modulus of similar to 18.8, i.e., a distance of similar to 57 kpc. Situated at 11 degrees.3 from the LMC in projection, its three-dimensional distance from the Cloud is similar to 13 kpc, consistent with a connection to the LMC, whose tidal radius is at least 16 kpc. Although the nature of SMASH 1 remains uncertain, its compactness favors it being a stellar cluster and hence dark-matter free. If this is the case, its dynamical tidal radius is only less than or similar to 19 pc at this distance from the LMC, and smaller than the system's extent on the sky. Its low luminosity and apparent high ellipticity (epsilon = 0.62(-0.21)(+0.17)) with its major axis pointing toward the LMC may well be the tell-tale sign of its imminent tidal demise.
We present ground-based {\it B} and {\it R}-band color-magnitude diagrams
(CMDs) of unprecedented depth for twelve fields in the Small Magellanic Cloud
(SMC). They reach the oldest main-sequence ...turnoffs and cover a wide range of
galactocentric distances up to $\sim4\arcdeg$ from the SMC center, and are
located at different position angles. A picture of the stellar content in our
SMC fields is presented, through the comparison with theoretical isochrones.
Our study confirms the existence of strong population gradients and spatial
variation in the SMC stellar content.
None of the SMC fields presented here are dominated by old stellar
populations which proves that at $\sim4\arcdeg$ from the SMC center we do not
reach an old stellar halo similar to that of the Milky Way.
The Large and Small Magellanic Clouds are unique local laboratories for studying the formation and evolution of small galaxies in exquisite detail. The Survey of the MAgellanic Stellar History ...(SMASH) is an NOAO community Dark Energy Camera (DECam) survey of the Clouds mapping 480 deg2 (distributed over similar to 2400 square degrees at similar to 20% filling factor) to similar to 24th. mag in ugriz. The primary goals of SMASH are to identify low surface brightness stellar populations associated with the stellar halos and tidal debris of the Clouds, and to derive spatially resolved star formation histories. Here, we present a summary of the survey, its data reduction, and a description of the first public Data Release (DR1). The SMASH DECam data have been reduced with a combination of the NOAO Community Pipeline, the PHOTRED automated point-spread-function photometry pipeline, and custom calibration software. The astrometric precision is similar to 15 mas and the accuracy is similar to 2 mas with respect to the Gaia reference frame. The photometric precision is similar to 0.5%-0.7% in griz and similar to 1% in u with a calibration accuracy of similar to 1.3% in all bands. The median 5s point source depths in ugriz are 23.9, 24.8, 24.5, 24.2, and 23.5 mag. The SMASH data have already been used to discover the Hydra II Milky Way satellite, the SMASH 1 old globular cluster likely associated with the LMC, and extended stellar populations around the LMC out to R. similar to. 18.4 kpc. SMASH DR1 contains measurements of similar to 100 million objects distributed in 61 fields. A prototype version of the NOAO Data Lab provides data access and exploration tools.
We present deep ground-based {\it B} and {\it R} observations of 12 fields in
the Small Magellanic Cloud (SMC). The resulting color-magnitude diagrams (CMDs)
reach the oldest main-sequence (MS) ...turnoff at M$_{R}$$\thicksim$3.5 and reveal
the stellar population differences between the part of the galaxy facing the
Large Magellanic Cloud (LMC) and an area on the opposite side. In the Southern
part of the galaxy, we found that there are still intermediate-age stars as far
as 4 kpc from the SMC center.
The Chemical Enrichment History (CEH) in one of our SMC fields is also
presented.
We present deep color-magnitud diagrams (CMDs) reaching the oldest main-sequence turnoffs for 12 fields in the SMC. The {\it B}-band and {\it R}-band observations were performed using the 100-inch ...Irénée du Pont telescope at Las Campanas Observatory, Chile, during four different campaigns (2001-2004). Our fields cover a wide range of galactocentric distance ranging from \(\sim1\deg\) to \(\sim4\deg\) from the center of the galaxy and are located a different position angles. Photometry was carried out using DAOPHOT II/ALLSTAR/ALLFRAME. Teramo isochrones have been overlapped. All our unprecedented deep ground-based CMDs reach the old MS turnoffs with very good photometric accuracy. They clearly show stellar population gradients as a function of both galactocentric distance and position angle. The most conspicuous difference involves the young population (age\(<\)1 Gyr): the young MS is much more populated on the eastern fields, located on the SMC wing area, than on the western fields located at similar galactocentric radius. In addition, the main stellar population gets progresively older on average as we go to larger galactocentric radius.
We present a progress report of a project to study the quantitative star formation history (SFH) in different parts of the Small Magellanic Cloud (SMC). We use the information in (B-R), R ...color-magnitude diagrams (CMDs), which reach down to the oldest main-sequence turnoffs and allow us to retrieve the SFH in detail. We show the first results of the SFH in a SMC field located in the Southern direction (at \(\thicksim\)1 kpc from the SMC center). This field is particularly interesting because in spite of being located in a place in which the HI column density is very low, it still presents a recent enhancement of star formation.
We present ground-based {\it B} and {\it R}-band color-magnitude diagrams (CMDs) of unprecedented depth for twelve fields in the Small Magellanic Cloud (SMC). They reach the oldest main-sequence ...turnoffs and cover a wide range of galactocentric distances up to \(\sim4\arcdeg\) from the SMC center, and are located at different position angles. A picture of the stellar content in our SMC fields is presented, through the comparison with theoretical isochrones. Our study confirms the existence of strong population gradients and spatial variation in the SMC stellar content. None of the SMC fields presented here are dominated by old stellar populations which proves that at \(\sim4\arcdeg\) from the SMC center we do not reach an old stellar halo similar to that of the Milky Way.
We present deep ground-based {\it B} and {\it R} observations of 12 fields in the Small Magellanic Cloud (SMC). The resulting color-magnitude diagrams (CMDs) reach the oldest main-sequence (MS) ...turnoff at M$_{R}$$\thicksim$3.5 and reveal the stellar population differences between the part of the galaxy facing the Large Magellanic Cloud (LMC) and an area on the opposite side. In the Southern part of the galaxy, we found that there are still intermediate-age stars as far as 4 kpc from the SMC center. The Chemical Enrichment History (CEH) in one of our SMC fields is also presented.
