83 research outputs found
Ongoing Mass Transfer in the Interacting Galaxy Pair NGC 1409/10
I present two-band HST STIS imaging, and WIYN spectral mapping, of ongoing
mass transfer in the interacting galaxy pair NGC 1409/10 (where NGC 1410 is the
Seyfert galaxy also catalogued as III Zw 55). Archival snapshot WFPC2 imaging
from the survey by Malkan et al. showed a dust feature stretching between the
galaxies, apparently being captured by NGC 1409. The new images allow estimates
of the mass being transferred and rate of transfer. An absorption lane
typically 0.25" (100 pc) wide with a representative optical depth tau_B = 0.2
cuts across the spiral structure of NGC 1410, crosses the 7-kpc projected space
between the nuclei, wraps in front of and, at the limits of detection, behind
NGC 1409, and becomes a denser (tau_B = 0.4) polar feature around the core of
NGC 1409. Combination of extinction data in two passbands allows a crude
three-dimensional recovery of the dust structure, supporting the front/back
geometry derived from colors and extinction estimates. The whole feature
contains of order solar masses in dust, implying about 2x10^7 solar
masses of gas, requiring a mass transfer rate averaging ~1 solar mass per year
unless we are particularly unlucky in viewing angle. Curiously, this
demonstrable case of mass transfer seems to be independent of the occurrence of
a Seyfert nucleus, since the Seyfert galaxy in this pair is the donor of the
material. Likewise, the recipient shows no signs of recent star formation from
incoming gas, although NGC 1410 has numerous luminous young star clusters and
widespread H-alpha emission.Comment: 27 pages, 9 figures. Accepted for the Astronomical Journal, March
200
Attosecond Streaking in the Water Window: A New Regime of Attosecond Pulse Characterization
We report on the first streaking measurement of water-window attosecond
pulses generated via high harmonic generation, driven by sub-2-cycle,
CEP-stable, 1850 nm laser pulses. Both the central photon energy and the energy
bandwidth far exceed what has been demonstrated thus far, warranting the
investigation of the attosecond streaking technique for the soft X-ray regime
and the limits of the FROGCRAB retrieval algorithm under such conditions. We
also discuss the problem of attochirp compensation and issues regarding much
lower photo-ionization cross sections compared with the XUV in addition to the
fact that several shells of target gases are accessed simultaneously. Based on
our investigation, we caution that the vastly different conditions in the soft
X-ray regime warrant a diligent examination of the fidelity of the measurement
and the retrieval procedure.Comment: 14 Pages, 12 figure
Distribution and Content of Dust in Overlapping Galaxy Systems
Partially overlapping galaxies are used to directly determine the effective
absorption in spiral galaxy disks. The non-overlapping parts of the galaxies
and symmetry considerations are used to reconstruct, via differential
photometry, how much background galaxy light is lost in passing through the
foreground disks.Comment: 4 PostScript pages; to appear in proceedings of "Dust-Morphology"
Conference, Johannesburg, South Africa, 22-26 January 1996, ed. D. Block
(Dordrecht: Kluwer); also available with 3 PostScript figures at
http://www.astr.ua.edu/preprints/white
Tailoring treatment of salivary duct carcinoma (SDC) by liquid biopsy: ARv7 expression in circulating tumor cells
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Observation and Control of Laser-Enabled Auger Decay
Single photon laser enabled Auger decay (spLEAD) has been redicted
theoretically [Phys. Rev. Lett. 111, 083004 (2013)] and here we report its
first experimental observation in neon. Using coherent, bichromatic
free-electron laser pulses, we have detected the process and coherently
controlled the angular distribution of the emitted electrons by varying the
phase difference between the two laser fields. Since spLEAD is highly sensitive
to electron correlation, this is a promising method for probing both
correlation and ultrafast hole migration in more complex systems.Comment: 5 pages, 3 figure
Small Scale Systems of Galaxies. III. X-ray detected E+S galaxy pairs in low density environments
We present a comprehensive study of the local environments of four E+S galaxy
pairs with the main goal to investigate their formation/evolution histories.
New XMM-Newton data were obtained for two pairs (RR 143 and RR 242) that
complements existing ROSAT data for the other two (RR 210 and RR 216). The new
observations reveal diffuse X-ray emission in both pairs. The emission is
asymmetric in both cases and extends out to 120 kpc and 160 kpc in RR 143 and
RR 242 respectively. The nucleus of RR 242 hosts a low luminosity mildly
absorbed AGN. We find that the early-type components of pairs with diffuse hot
gas appear to be relaxed objects while those in RR 210 and RR 216, where no
diffuse emission has been found, display unambiguous signatures of ongoing
interaction. Wide-field V and R-band data are used to study the photometric
properties of the early-type components and to search for a candidate faint
galaxy populations around each of the pairs. While no diffuse optical light is
found for any of the pairs, all of the early-type members show very extended
and concentric luminous envelopes. We identify a faint galaxy sample in each
field and we consider whether they could be physically associated with the
luminous pairs based upon (V-R) colors and photometric properties. We find that
the distribution of r_e and M_R for the candidates are similar in three of the
fields (RR 143, 216 and 242). The same selection criteria applied to the field
of RR 210 suggest a fainter and more compact population possibly suggesting a
larger background fraction than in the other fields.Comment: 47 pages, 18 figures, Astron. J. in pres
XL Convegno Internazionale del G.I.R.E.A. âLe realtĂ della schiavitĂč: identitĂ e biografie da Eumeo a Frederick Douglass. Les rĂ©alitĂ©s de lâesclavage: identitĂ©s et biographies dâEumĂ©e Ă Frederick Douglassâ. Napoli, 18-20 dicembre 2017 Centro Congressi Federico II
Small scale systems of galaxies I. Photometric and spectroscopic properties of members
This paper is the first of a series addressed to the investigation of galaxy
formation/evolution in small scale systems of galaxies (SSSGs) which are
located in low density cosmic environments. Our algorithm for SSSG selection
includes galaxy systems of 2 or more galaxies lying within 1000 km/s and a 200
h_{100}^{-1} kpc radius volume. We present the analysis of the photometric and
spectroscopic properties of 19 member galaxies belonging to a sample of 11
SSSGs.
In the plane, early-type members may be considered "ordinary",
not "bright" galaxies in the definition given by Capaccioli et al.(1992) with a
significant fraction of galaxies having a disk or disky isophotes. We do not
detect fine structure and signatures of recent interaction events in the
early-type galaxy population, a picture also confirmed by the spectroscopy.
At odd, there are several spiral members with open arm configurations as
expected in interacting systems. At the same time, emission lines in the
spectra of spiral members fall in the HII regions regime defined with
diagnostic diagrams (Veilleux & Osterbrock 1987). None of the objects displays
unambiguous indication of nuclear activity, although fourspiral nuclei could be
ascribed to the class of Seyferts. The star formation rate seems enhanced over
the average expected in spiral galaxies only for poorer SSSGs in particular
pairs (<50 solar masses per year) but without being in the range of starburst
systems.Comment: 24 pages, including 6 figures and 6 tables. Accepted for publication
in A
Merging Galaxies in the SDSS EDR
We present a new catalog of merging galaxies obtained through an automated
systematic search routine. The 1479 new pairs of merging galaxies were found in
approximately 462 sq deg of the Sloan Digital Sky Survey Early Data Release
(SDSS EDR; Stoughton et al. 2002) photometric data, and the pair catalog is
complete for galaxies in the magnitude range 16.0 <= g* <= 20.
The selection algorithm, implementing a variation on the original
Karachentsev (1972) criteria, proved to be very efficient and fast. Merging
galaxies were selected such that the inter-galaxy separations were less than
the sum of the component galaxies' radii.
We discuss the characteristics of the sample in terms of completeness, pair
separation, and the Holmberg effect. We also present an online atlas of images
for the SDSS EDR pairs obtained using the corrected frames from the SDSS EDR
database. The atlas images also include the relevant data for each pair member.
This catalog will be useful for conducting studies of the general
characteristics of merging galaxies, their environments, and their component
galaxies. The redshifts for a subset of the interacting and merging galaxies
and the distribution of angular sizes for these systems indicate the SDSS
provides a much deeper sample than almost any other wide-area catalog to date.Comment: 58 pages, which includes 15 figures and 6 tables. Figures 2, 8, 9,
10, 11, 13, and 14 are provided as JPEG files. For online atlas, see
http://home.fnal.gov/~sallam/MergePair/ . Accepted for publication in A
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