Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The infrared Hourglass cluster in M8   A detailed study of the Hourglass Nebula in the M8 star forming region is
presented. The study is mainly based on recent subarcsec-resolution JHKs images
taken at Las Campanas Observatory and complemented with archival HST images and
longslit spectroscopy retrieved from the ESO Archive Facility. Using the new
numerical code CHORIZOS, we estimate the distance to the earliest stars in the
region to be 1.25 kpc. Infrared photometry of all the sources detected in the
field is given. From analysis of the JHKs colour-colour diagrams, we find that
an important fraction of these sources exhibit significant infrared excess.
These objects are candidates to be low- and intermediate-mass pre-main sequence
stars. Based on HST observations, the spatial distribution of gas, dust and
stars in the region is analyzed. The morphological analysis of these images
also reveals a rich variety of structures related to star formation (proplyds,
jets, bow shocks), similar to those observed in M16 and M42, along with the
detection of the first four Herbig-Haro objects in the region. Furthermore, a
longslit spectrum obtained with NTT confirms the identification of one of them
(HH 870) in the core of the Hourglass nebula, providing the first direct
evidence of active star formation by accretion in M8.

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The categories of this paper are: adap-org
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The categories of this paper are: math
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The categories of this paper are: hep-th
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The categories of this paper are: q-alg
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The categories of this paper are: dg-ga
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The categories of this paper are: cond-mat
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The categories of this paper are: chao-dyn
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The categories of this paper are: hep-ph
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The categories of this paper are: nlin
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The categories of this paper are: eess
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The categories of this paper are: gr-qc
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The categories of this paper are: mtrl-th
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The categories of this paper are: alg-geom
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The categories of this paper are: math-ph
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The categories of this paper are: cs
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The categories of this paper are: funct-an