39 research outputs found

    Mythical Critique of the Hero's Journey in "Sam Nameh" Poem According to Campbell's Theory

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    By introducing the theory of individuality, Jung has opened a new chapter in literary criticism and provided a forum for the activities of many contemporary theorists, including Joseph Campbell. Campbell, enumerate one of the common themes in myths that have a similar structure to each other and follow the single target as the hero's adventurous journey and according to that brought up the monomyth theory. In this research, enlisting from the myth criticism method and according to Campbell's classification, the hero's journey in Sam Namehā€™s poem that occurs in romantic adventure format was checked. Findings of research show that although the order of total pattern is not observed in this journey and all of the levels were not performed completely, the hero's journey differs slightly from Campbell's pattern. The hero at his own symbolic journey, with the discovery and recognition of the unknown and damaged aspects of his own psyche, was able to shape his shattered and unbalanced character by passing beyond the boundaries of his - limited- self and experiencing his own individuality by psychological evolution

    Dependence of the IRX-Ī² Dust Attenuation Relation on Metallicity and Environment

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    We use a sample of star-forming field and protocluster galaxies at z = 2.0ā€“2.5 with Keck/MOSFIRE K-band spectra, a wealth of rest-frame ultraviolet (UV) photometry, and Spitzer/MIPS and Herschel/PACS observations, to dissect the relation between the ratio of infrared (IR) to UV luminosity (IRX) versus UV slope (Ī²) as a function of gas-phase metallicity (12+log(O/H) ~ 8.2ā€“8.7). We find no significant dependence of the IRX-Ī² trend on environment. However, we find that at a given Ī², IRX is highly correlated with metallicity, and less correlated with mass, age, and specific star formation rate (sSFR). We conclude that, of the physical properties tested here, metallicity is the primary physical cause of the IRX-Ī² scatter, and the IRX correlation with mass is presumably due to the mass dependence on metallicity. Our results indicate that the UV attenuation curve steepens with decreasing metallicity, and spans the full range of slope possibilities from a shallow Calzetti-type curve for galaxies with the highest metallicity in our sample (12+log(O/H) ~ 8.6) to a steep Small Magellanic Cloud (SMC)-like curve for those with 12+log(O/H) ~ 8.3. Using a Calzetti (SMC) curve for the low (high) metallicity galaxies can lead to up to a factor of 3 overestimation (underestimation) of the UV attenuation and obscured star formation rate. We speculate that this change is due to different properties of dust grains present in the interstellar medium of low- and high-metallicity galaxies

    Dependence of the IRX-Ī²\beta dust attenuation relation on metallicity and environment

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    We use a sample of star-forming field and protocluster galaxies at z=2.0-2.5 with Keck/MOSFIRE K-band spectra, a wealth of rest-frame UV photometry, and Spitzer/MIPS and Herschel/PACS observations, to dissect the relation between the ratio of IR to UV luminosity (IRX) versus UV slope (Ī²\beta) as a function of gas-phase metallicity (12+log(O/H)~8.2-8.7). We find no significant dependence of the IRX-Ī²\beta trend on environment. However, we find that at a given Ī²\beta, IRX is highly correlated with metallicity, and less correlated with mass, age, and sSFR. We conclude that, of the physical properties tested here, metallicity is the primary physical cause of the IRX-Ī²\beta scatter, and the IRX correlation with mass is presumably due to the mass dependence on metallicity. Our results indicate that the UV attenuation curve steepens with decreasing metallicity, and spans the full range of slope possibilities from a shallow Calzetti-type curve for galaxies with the highest metallicity in our sample (12+log(O/H)~8.6) to a steep SMC-like curve for those with 12+log(O/H)~8.3. Using a Calzetti (SMC) curve for the low (high) metallicity galaxies can lead to up to a factor of 3 overestimation (underestimation) of the UV attenuation and obscured SFR. We speculate that this change is due to different properties of dust grains present in the ISM of low- and high-metallicity galaxies.Comment: Accepted for publication in ApJ

    Bridging between the integrated and resolved main sequence of star formation

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    The position of galaxies on the stellar mass, star formation rate (SFR) plane with respect to the star-forming main sequence at each redshift is a convenient way to infer where the galaxy is in its evolution compared to the rest of the population. We use Hubble Space Telescope high-resolution images in the GOODS-S field from the the Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey (CANDELS) and fit multiwavelength lights in resolution elements of galaxies with stellar population synthesis models. We then construct resolved kpc-scale stellar mass, SFR surface density curves for galaxies at z ~ 1. Fitting these resolved main sequence curves with Schechter functions, we parameterize and explain the multiwavelength structure of galaxies with three variables: Ļ†*, Ī±, and M*. For quenched galaxies below the main sequence, we find an average high-mass slope (Ī±) of the resolved main sequence curves to be ~āˆ’0.4. The scatter of this slope is higher among the lower mass star-forming galaxies and those above the main sequence compared to quenched galaxies, due to lack of an evolved bulge. Our findings agree well with an inside-out quenching of star formation. We find that the knee of the Schechter fits (M*) for galaxies below the main sequence occurs at lower stellar mass surface densities compared to star-forming galaxies, which hints at how far quenching has proceeded outward

    Bridging between the integrated and resolved main sequence of star formation

    Get PDF
    The position of galaxies on the stellar mass, star formation rate (SFR) plane with respect to the star-forming main sequence at each redshift is a convenient way to infer where the galaxy is in its evolution compared to the rest of the population. We use Hubble Space Telescope high-resolution images in the GOODS-S field from the the Cosmic Assembly Near-IR Deep Extragalactic Legacy Survey (CANDELS) and fit multiwavelength lights in resolution elements of galaxies with stellar population synthesis models. We then construct resolved kpc-scale stellar mass, SFR surface density curves for galaxies at z ~ 1. Fitting these resolved main sequence curves with Schechter functions, we parameterize and explain the multiwavelength structure of galaxies with three variables: Ļ†*, Ī±, and M*. For quenched galaxies below the main sequence, we find an average high-mass slope (Ī±) of the resolved main sequence curves to be ~āˆ’0.4. The scatter of this slope is higher among the lower mass star-forming galaxies and those above the main sequence compared to quenched galaxies, due to lack of an evolved bulge. Our findings agree well with an inside-out quenching of star formation. We find that the knee of the Schechter fits (M*) for galaxies below the main sequence occurs at lower stellar mass surface densities compared to star-forming galaxies, which hints at how far quenching has proceeded outward

    Spectroscopic confirmation of a Coma Cluster progenitor at z~2.2

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    We report the spectroscopic confirmation of a new protocluster in the COSMOS field at z āˆ¼ 2.2, originally identified as an overdensity of narrow-band selected HĪ± emitting candidates. With only two masks of Keck/MOSFIRE near-IR spectroscopy in both H (āˆ¼ 1.47-1.81 Ī¼m) and K (āˆ¼ 1.92- 2.40 Ī¼m) bands (āˆ¼ 1.5 hour each), we confirm 35 unique protocluster members with at least two emission lines detected with S/N > 3. Combined with 12 extra members from the zCOSMOS-deep spectroscopic survey (47 in total), we estimate a mean redshift, line-of-sight velocity dispersion, and total mass of zmean=2.23224 Ā± 0.00101, Ļƒlos=645 Ā± 69 km sāˆ’1, and Mvir āˆ¼ (1 āˆ’ 2)Ɨ10^14 MāŠ™ for this protocluster, respectively. We estimate a number density enhancement of Ī“g āˆ¼ 7 for this system and we argue that the structure is likely not virialized at z āˆ¼ 2.2. However, in a spherical collapse model, Ī“g is expected to grow to a linear matter enhancement of āˆ¼ 1.9 by z=0, exceeding the collapse threshold of 1.69, and leading to a fully collapsed and virialized Coma-type structure with a total mass of Mdyn(z=0) āˆ¼ 9.2Ɨ10^14 MāŠ™ by now. This observationally efficient confirmation suggests that large narrow-band emission-line galaxy surveys, when combined with ancillary photometric data, can be used to effectively trace the large-scale structure and protoclusters at a time when they are mostly dominated by star-forming galaxies

    The Lyman Continuum Escape Fraction of Star-forming Galaxies at 2.4ā‰²zā‰²3.72.4\lesssim z\lesssim3.7 from UVCANDELS

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    The UltraViolet Imaging of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey Fields (UVCANDELS) survey is a Hubble Space Telescope (HST) Cycle-26 Treasury Program, allocated in total 164 orbits of primary Wide-Field Camera 3 Ultraviolet and Visible light F275W imaging with coordinated parallel Advanced Camera for Surveys F435W imaging, on four of the five premier extragalactic survey fields: GOODS-N, GOODS-S, EGS, and COSMOS. We introduce this survey by presenting a thorough search for galaxies at zā‰³2.4z\gtrsim2.4 that leak significant Lyman continuum (LyC) radiation, as well as a stringent constraint on the LyC escape fraction (fescf_{\rm esc}) from stacking the UV images of a population of star-forming galaxies with secure redshifts. Our extensive search for LyC emission and stacking analysis benefit from the catalogs of high-quality spectroscopic redshifts compiled from archival ground-based data and HST slitless spectroscopy, carefully vetted by dedicated visual inspection efforts. We report a sample of five galaxies as individual LyC leaker candidates, showing fescrelā‰³60%f_{\rm esc}^{\rm rel}\gtrsim60\% estimated using detailed Monte Carlo analysis of intergalactic medium attenuation. We develop a robust stacking method to apply to five samples of in total 85 non-detection galaxies in the redshift range of zāˆˆ[2.4,3.7]z\in[2.4,3.7]. Most stacks give tight 2-Ļƒ\sigma upper limits below fescrel<6%f_{\rm esc}^{\rm rel}<6\%. A stack for a subset of 32 emission-line galaxies shows tentative LyC leakage detected at 2.9-Ļƒ\sigma, indicating fescrel=5.7%f_{\rm esc}^{\rm rel}=5.7\% at zāˆ¼2.65z\sim2.65, supporting the key role of such galaxies in contributing to the cosmic reionization and maintaining the UV ionization background. These new F275W and F435W imaging mosaics from UVCANDELS have been made publicly available on the Barbara A. Mikulski Archive for Space Telescopes.Comment: 33 pages, 21 figures, and 5 tables. Resubmitted after addressing the referee repor

    The Ultraviolet Luminosity Function at 0.6 < z < 1 from UVCANDELS

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    UVCANDELS is a Hubble Space Telescope Cycle-26 Treasury Program awarded 164 orbits of primary ultraviolet (UV) F275W imaging and coordinated parallel optical F435W imaging in four CANDELS fieldsā€”GOODS-N, GOODS-S, EGS, and COSMOSā€”covering a total area of āˆ¼426 arcmin2. This is āˆ¼2.7 times larger than the area covered by previous deep-field space UV data combined, reaching a depth of about 27 and 28 ABmag (5Ļƒ in 0.ā€2 apertures) for F275W and F435W, respectively. Along with new photometric catalogs, we present an analysis of the rest-frame UV luminosity function (LF), relying on our UV-optimized aperture photometry method, yielding a factor of 1.5 increase over H-isophot aperture photometry in the signal-to-noise ratios of galaxies in our F275W imaging. Using well-tested photometric redshift measurements, we identify 5810 galaxies at redshifts 0.6 &lt; z &lt; 1, down to an absolute magnitude of M UV = āˆ’14.2. In order to minimize the effect of uncertainties in estimating the completeness function, especially at the faint end, we restrict our analysis to sources above 30% completeness, which provides a final sample of 4726 galaxies at āˆ’21.5 &lt; M UV &lt; āˆ’15.5. We performed a maximum likelihood estimate to derive the best-fit parameters of the UV LF. We report a best-fit faint-end slope of Ī±=āˆ’1.359āˆ’0.041+0.041 at z āˆ¼ 0.8. Creating subsamples at z āˆ¼ 0.7 and z āˆ¼ 0.9, we observe a possible evolution of Ī± with redshift. The unobscured UV luminosity density at M UV &lt; āˆ’10 is derived as ĻUV=1.339āˆ’0.030+0.027(Ɨ1026ergsāˆ’1Hzāˆ’1Mpcāˆ’3) using our best-fit LF parameters. The new F275W and F435 photometric catalogs from UVCANDELS have been made publicly available on the Barbara A. Mikulski Archive for Space Telescopes
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