2,553 research outputs found
Weighted -summability of fuzzy functions of order
The concept of weighted - summability of order in case
of fuzzy functions is introduced and classified into ordinary and absolute
sense. Several inclusion relations among the sets are investigated. Also we
have found some suitable conditions to get its relation with the generalized
statistical convergence. Finally we have proved a generalized version of
Tauberian theorem
The embedded ring-like feature and star formation activities in G35.673-00.847
We present a multi-wavelength study to probe the star formation (SF) process
in the molecular cloud linked with the G35.673-00.847 site (hereafter MCG35.6),
which is traced in a velocity range of 53-62 km/s. Multi-wavelength images
reveal a semi-ring-like feature (associated with ionized gas emission) and an
embedded face-on ring-like feature (without the NVSS 1.4 GHz radio emission;
where 1-sigma ~ 0.45 mJy/beam) in the MCG35.6. The semi-ring-like feature is
originated by the ionizing feedback from a star with spectral type B0.5V-B0V.
The central region of the ring-like feature does not contain detectable ionized
gas emission, indicating that the ring-like feature is unlikely to be produced
by the ionizing feedback from a massive star. Several embedded Herschel clumps
and young stellar objects (YSOs) are identified in the MCG35.6, tracing the
ongoing SF activities within the cloud. The polarization information from the
Planck and GPIPS data trace the plane-of-sky magnetic field, which is oriented
parallel to the major axis of the ring-like feature. At least five clumps
(having M_clump ~ 740 - 1420 M_sun) seem to be distributed in an almost
regularly spaced manner along the ring-like feature and contain noticeable
YSOs. Based on the analysis of the polarization and molecular line data, three
subregions containing the clumps are found to be magnetically supercritical in
the ring-like feature. Altogether, the existence of the ring-like feature and
the SF activities on its edges can be explained by the magnetic field mediated
process as simulated by Li & Nakamura (2002).Comment: 26 pages, 12 figures, 5 tables. Accepted for publication in The
Astrophysical Journa
Massive young stellar object W42-MME: The discovery of an infrared jet using VLT/NACO near-infrared images
We report on the discovery of an infrared jet from a deeply embedded infrared
counterpart of 6.7 GHz methanol maser emission (MME) in W42 (i.e. W42-MME). We
also investigate that W42-MME drives a parsec-scale H2 outflow, with detection
of bow shock feature at ~0.52 pc to the north. The inner ~0.4 pc part of the H2
outflow has a position angle of ~18 deg and the position angle of ~40 deg is
found farther away on either side of outflow from W42-MME. W42-MME is detected
at wavelengths longer than 2.2 microns and is a massive young stellar object,
with the estimated stellar mass of 19+-4 Msun. We map the inner circumstellar
environment of W42-MME using VLT/NACO adaptive optics Ks and L' observations at
resolutions ~0.2 arcsec and ~0.1 arcsec, respectively. We discover a collimated
jet in the inner 4500 AU using the L' band, which contains prominent Br alpha
line emission. The jet is located inside an envelope/cavity (extent ~10640 AU)
that is tapered at both ends and is oriented along the north-south direction.
Such observed morphology of outflow cavity around massive star is scarcely
known and is very crucial for understanding the jet-outflow formation process
in massive star formation. Along the flow axis, which is parallel to the
previously known magnetic field, two blobs are found in both the NACO images at
distances of ~11800 AU, located symmetrically from W42-MME. The observed
W42-MME jet-outflow configuration can be used to constrain the jet launching
and jet collimation models in massive star formation.Comment: 6 pages, 5 figures, Accepted for publication in The Astrophysical
Journa
Embedded filaments in IRAS 05463+2652: early stage of fragmentation and star formation activities
We present a multi-wavelength data analysis of IRAS 05463+2652 (hereafter
I05463+2652) to study star formation mechanisms. A shell-like structure around
I05463+2652 is evident in the Herschel column density map, which is not
associated with any ionized emission. Based on the Herschel sub-millimeter
images, several parsec-scale filaments (including two elongated filaments,
"s-fl" and "nw-fl" having lengths of ~6.4 pc and ~8.8 pc, respectively) are
investigated in I05463+2652 site. Herschel temperature map depicts all these
features in a temperature range of ~11-13 K. 39 clumps are identified and have
masses between ~70-945 M. A majority of clumps (having M_clump >= 300
M) are distributed toward the shell-like structure. 175 young stellar
objects (YSOs) are selected using the photometric 1-5 microns data and a
majority of these YSOs are distributed toward the four areas of high column
density >= 5 x 10^{21} cm^{-2}; A_V ~5.3 mag) in the shell-like structure,
where massive clumps and a spatial association with filament(s) are also
observed. The knowledge of observed masses per unit length of elongated
filaments and critical mass length reveals that they are supercritical. The
filament "nw-fl" is fragmented into five clumps (having M_clump ~100-545
M) and contains noticeable YSOs, while the other filament "s-fl" is
fragmented into two clumps (having M_clump ~170-215 M) without YSOs.
Together, these observational results favor the role of filaments in star
formation process in I05480+2545. This study also reveals the filament "s-fl",
containing two starless clumps, at an early stage of fragmentation.Comment: 13 pages, 6 figures, 1 table, Accepted for publication in The
Astrophysical Journa
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