相关论文: Modelling the red halos of blue compact galaxies
Red halos are faint, extended and extremely red structures that have been reported around various types of galaxies since the mid-1990s. The colours of these halos are too red to be reconciled with any hitherto known type of stellar…
Optical and near-IR observations of the halos of disk galaxies and blue compact galaxies have revealed a very red spectral energy distribution, which cannot easily be reconciled with a normal, metal-poor stellar population like that in the…
Deep optical/near-IR surface photometry of galaxies outside the Local Group have revealed faint and very red halos around objects as diverse as disk galaxies and starbursting dwarf galaxies. The colours of these structures are too extreme…
We present optical spectroscopy and deep optical/near-IR photometry of 4 luminous metal-poor blue compact galaxies (BCGs) and two of their companions. With the aid of spectral evolutionary models (SEMs) and structural parameters derived…
Deep surface photometry of disk galaxies at optical and near-IR wavelengths have revealed faint halos with colours much too red to be reconciled with the resolved stellar populations detected in the halos of the Milky Way or M31.…
Blue compact galaxies (BCGs) are compact galaxies that are dominated by intense star formation. Comparing the observational properties with the predictions of stellar population synthesis model, we have analyzed the nuclear stellar…
Surface photometry detections of red and exceedingly faint halos around galaxies have resurrected the old question of whether some non-negligible fraction of the missing baryons of the Universe could be hiding in the form of faint,…
The faint stellar halos of galaxies contain key information about the oldest stars and the process of galaxy formation. A previous study of stacked SDSS images of disk galaxies has revealed a halo with an abnormally red r-i colour,…
Using the Hubble Space Telescope, we have resolved individual red-giant branch stars in the halos of eight nearby spiral galaxies. The fields lie at projected distances between 2 and 13 kpc along the galaxies' minor axes. The data set…
We present the resolved stellar populations in the inner and outer halo of the nearby lenticular galaxy NGC~3115. Using deep HST observations, we analyze stars two magnitudes fainter than the tip of the red giant branch (TRGB). We study…
The puzzling origin of the ``UV-upturn'' phenomenon, observed in some elliptical galaxies, has recently been settled by identifying hot HB stars as main contributors to galaxy ultraviolet luminosity excess. While a blue HB morphology seems…
Previous studies of the low surface brightness host of the blue compact galaxy (BCG) Haro 11 have suggested an abnormally red color of V-K=4.2+-0.8 for the host galaxy. This color is inconsistent with any normal stellar population over a…
We study the formation and evolution of stellar halos (SHs) around bright central galaxies (BCGs), focusing on their scaling relations, colors, and metallicities across cosmic time, and compare model predictions with ultra--deep imaging…
By combining optical and near-IR observations from the Hubble Space Telescope with NIR photometry from the Spitzer Space Telescope it is possible to measure the rest-frame UV-optical colours of galaxies at z=4-8. The UV-optical spectral…
An increasing body of data reveals a one-to-one linear correlation between galaxy halo mass and the total mass in its globular cluster (GC) population, M_{GCS} ~ M_h^{1.03 \pm 0.03}, valid over 5 orders of magnitude. We explore the nature…
The high spatial resolution of the Hubble Space Telescope (HST) has led to tremendous progress in many areas of astronomy. The ability of the HST to peer into the bright inner regions of galaxies and distinguish between globular clusters…
(Abriged) We report results of a campaign to image the stellar populations in the halos of highly inclined spiral galaxies, with the fields roughly 10 kpc (projected) from the nuclei. We use the F814W (I) and F606W (V) filters in the Wide…
High-resolution optical spectra of thirteen blue horizontal-branch (BHB) stars in the globular cluster M13 show enormous deviations in element abundances from the expected cluster metallicity. In the hotter stars (T_eff > 12000 K), helium…
To address the puzzling photometric properties of horizontal branch stars in Galactic GCs, several different groups have undertaken detailed spectroscopic analyses of individual blue HB stars. Hotter BHB stars show strong metal enhancement…
The mean color of globular clusters (GCs) in early-type galaxies is in general bluer than the integrated color of halo field stars in host galaxies. Metal-rich GCs often appear more associated with field stars than metal-poor GCs, yet show…