Thasos

HOLTZMANN, Bernard; Grandjean, Yves; Koukouli, Haïdo; Martin, Roland; Müller, Arthur; Garlan, Yvon; Kozelj, Tony; Maffre, Jean-Jacques; Hadjimichali, Vanna

doi:10.3406/bch.1979.6604

Cited by 6 publications

(5 citation statements)

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“…Such super star clusters are observed in a growing number of starburst systems and may constitute an important mode of star formation in starbursts (e.g. Holtzmann et al 1992;O'Connell, Gallagher, & Hunter 1994;Whitmore & Schweizer 1995;Maoz et al 1996;Tacconi-Garman, Sternberg, & Eckart 1996).…”

Section: A2 Properties and Distribution Of The Ionizing Stellar Clumentioning

confidence: 99%

Near‐Infrared Integral Field Spectroscopy and Mid‐Infrared Spectroscopy of the Starburst Galaxy M82

Schreiber

Genzel

Lutz

et al. 2001

ApJ

127

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We present new infrared observations of the central regions of the starburst galaxy M 82. The observations consist of near-infrared integral field spectroscopy in the H-and K-band obtained with the MPE 3D instrument, and of λ = 2.4 − 45 µm spectroscopy from the Short Wavelength Spectrometer (SWS) on board the Infrared Space Observatory. These measurements are used, together with data from the literature, to (1) re-examine the controversial issue of extinction, (2) determine the physical conditions of the interstellar medium (ISM) within the star-forming regions, and (3) characterize the composition of the stellar populations. Our results provide a set of constraints for detailed starburst modeling which we present in a companion paper.We find that purely foreground extinction cannot reproduce the global relative intensities of H recombination lines from optical to radio wavelengths. A good fit is provided by a homogeneous mixture of dust and sources, and with a visual extinction of A V = 52 mag. The SWS data provide evidence for deviations from commonly assumed extinction laws between 3 µm and 10 µm. The fine-structure lines of Ne, Ar, and S detected with SWS imply an electron density of ≈ 300 cm −3 , and abundance ratios Ne/H and Ar/H nearly solar and S/H about one-fourth solar. The excitation of the ionized gas indicates an average effective temperature for the OB stars of 37400 K, with little spatial variation across the starburst regions. We find that a random distribution of closely packed gas clouds and ionizing clusters, and an ionization parameter of ≈ 10 −2.3 represent well the star-forming regions on spatial scales ranging from a few tens to a few hundreds of parsecs. From detailed population synthesis and the mass-to-K-light ratio, we conclude that the near-infrared continuum emission across the starburst regions is dominated by red supergiants with average effective temperatures ranging from 3600 K to 4500 K, and roughly solar metallicity. Our data rule out significant contributions from older, metal-rich giants in the central few tens of parsecs of M 82.

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Section: A2 Properties and Distribution Of The Ionizing Stellar Clumentioning

confidence: 99%

Near‐Infrared Integral Field Spectroscopy and Mid‐Infrared Spectroscopy of the Starburst Galaxy M82

Schreiber

Genzel

Lutz

et al. 2001

ApJ

127

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“…Two of the many interesting phenomena discovered by the satellite observatories have been the starburst galaxies and the super star clusters, first identified as important classes by the IRAS and the Hubble Space Telescope (HST) satellites (Soifer et al 1987;Holtzmann et al 1992). The starburst galaxies are characterized by extremely rapid star formation in regions with gas densities up to 20 times higher than the typical densities of normal spiral galaxies (Sanders & Mirabel 1996).…”

Section: Introductionmentioning

confidence: 99%

“…Estimates of SSC masses based on population synthesis models indicate a range from below 10 4 up to a few 10 6 M ⊙ Melo et al 2005). The similarity in size and mass of the SSCs and globular clusters have prompted the further suggestion that the SSCs might be present-day analogs of young globular clusters (Holtzmann et al 1992). Previously thought to form strictly in an earlier epoch of galaxy evolution, globular clusters may in fact be forming in the current epoch in starburst environments (Ashman & Zepf 2001).…”

Section: Introductionmentioning

confidence: 99%

M82, Starbursts, Star Clusters, and the Formation of Globular Clusters

Keto

2005

ApJ

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We observed the nearby starburst galaxy M82 in CO in the higher frequency (2--1) transition to achieve an angular resolution below 1 arc second or 17 pc at the target. We resolved the molecular gas into a large number of compact clouds, with masses ranging from about 2x10^3 to 2x10^6 solar masses. The mass spectrum scales as N(M) ~ M^-1.5, similar to the mass spectra of young massive star clusters suggesting that individual molecular clouds are transformed in the starburst into individual star clusters. The larger clouds are surrounded by supernovae and HII regions suggesting that star formation proceeds from the outside of the clouds and progresses inward consistent with triggering by a sudden increase in external pressure. The clouds with internal star formation have velocity gradients and inverse P-Cygni spectral line profiles indicating inward motions of 35 kms consistent with shock driven compression. Diffuse free-free radio emission and X-ray emission around the clouds provides evidence for superheated ionized gas sufficient to drive the compression. Clouds with spectral lines indicating expansion show little internal star formation suggesting that the dynamics precedes and is responsible for the star formation rather than the inverse. M82 is known to be in interaction with neighboring M81. The overall picture is consistent with the formation of massive star clusters from individual giant molecular clouds crushed by a sudden galactic scale increase in external pressure generated by the changing dynamics that result from a near-collision with a neighboring galaxy. Present day globular clusters may have formed in a similar fashion in primordial galaxies.Comment: Submitted to Ap

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“…Of the two towers found inside the defended area, the tower located at the western part of the fortress (T1 in Fig. 5) was still standing in 1931, when it was demolished for the building of the new museum (Holtzmann 1979, 635–6; Grandjean and Salviat 2000, 35). It was of rectangular plan (14 m × 10.6 m) with a small projection on the north side where also the entrance to the tower was located (Giros 1991, 46).…”

Section: The Profile Of a Late Byzantine Borderlordmentioning

confidence: 99%

Lords at the End of the Empire: Negotiating Power in the Late Byzantine Frontiers (Fourteenth–fifteenth Centuries)

Kondyli

2017

Annu. Br. Sch. Athens

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The defence of Late Byzantine (fourteenth–fifteenth centuries) frontier zones frequently became the responsibility of military elites, borderlords, who enjoyed absolute power in these areas and immunity from any fiscal or other obligation towards the Byzantine state. In this article I present the case studies of two borderlord families: the brothers and military officials Alexios and John, and the Genoese family of the Gattilusi, who ruled large areas around the Northern Aegean in the fourteenth and fifteenth centuries and participated actively in their defence at a time when they were surrounded by enemies and plagued by piracy. The aim of the article is twofold. First, I consider the borderlords’ building activities, modes of self-representation and the creation of new geographies as strategies for establishing control and legitimising their power. Second, I explore how the rise of these borderlords fits with Byzantine imperial policies and corresponds to changes in the character of Late Byzantine imperial authority and the role of the Byzantine emperor within and beyond the empire. Over the course of this article I hope to highlight the complexity of the political and economic situation in the fourteenth and fifteenth centuries and contribute to an understanding of modes of Late Byzantine government and power that move beyond simplistic frameworks of decline and fall.

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Thasos

Cited by 6 publications

References 1 publication

Near‐Infrared Integral Field Spectroscopy and Mid‐Infrared Spectroscopy of the Starburst Galaxy M82

Near‐Infrared Integral Field Spectroscopy and Mid‐Infrared Spectroscopy of the Starburst Galaxy M82

M82, Starbursts, Star Clusters, and the Formation of Globular Clusters

Lords at the End of the Empire: Negotiating Power in the Late Byzantine Frontiers (Fourteenth–fifteenth Centuries)

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