118 research outputs found
RESEARCH-BASED LEARNING: EFFECTS ON THE METACOGNITIVE AWARENESS OF SENIOR HIGH SCHOOL STUDENTS
This research study assessed the effects of research-based learning (RBL) on the metacognitive awareness of senior high school (SHS) students, specifically metacognitive knowledge and metacognitive regulation, and the correlation between their subcomponents. Fifty-six (56) Grade 12 students who have taken research subjects were obtained as respondents using purposive sampling. The respondents answered a 52-item metacognitive awareness inventory (MAI) with 17 items on metacognitive knowledge and 35 items on metacognitive regulation. Findings show that RBL developed a high level of conditional, procedural, and declarative knowledge among SHS students. The learning approach also developed a very high level of debugging strategies, and a high level of planning, information management system, evaluation, and comprehension monitoring. Furthermore, there is a weak or a moderately significant positive correlation between some subcomponents of metacognitive knowledge and metacognitive regulation as the effect of RBL. In conclusion, RBL has a considerable impact on the metacognitive awareness subcomponents of Grade 12 students.Corresponding author:Mark Anthony Catedral MamonDOI: 10.24071/ijiet.2020.04021
Wolves in the Wolds: Late Capitalism, the English Eerie, and the Wyrd Case of ‘Old Stinker’ the Hull Werewolf
In this article, I depart from the earlier opinions of Emily Gerard, Sabine Baring-Gould, and others, who explained the disappearance of the werewolf in folklore as following the extinction of the wolf. I argue instead that British literature is distinctive in representing a history of werewolf sightings in places in Britain where there were once wolves. I draw on the idea of absence, manifestations of the English eerie, and the turbulence of England in the era of late capitalism to illuminate my analysis of the representation of contemporary werewolf sightingsPeer reviewe
Near-infrared emission line diagnostics for AGN from the local Universe to redshift 3
Optical rest-frame spectroscopic diagnostics are usually employed to
distinguish between star formation and AGN-powered emission. However, this
method is biased against dusty sources, hampering a complete census of the AGN
population across cosmic epochs. To mitigate this effect, it is crucial to
observe at longer wavelengths in the rest-frame near-infrared (near-IR), which
is less affected by dust attenuation and can thus provide a better description
of the intrinsic properties of galaxies. AGN diagnostics in this regime have
not been fully exploited so far, due to the scarcity of near-IR observations of
both AGNs and star-forming galaxies, especially at redshifts higher than 0.5.
Using Cloudy photoionization models, we identify new AGN - star formation
diagnostics based on the ratio of bright near-infrared emission lines, namely
[SIII] 9530 Angstrom, [CI] 9850 Angstrom, [PII] 1.188 , [FeII] , and [FeII] to Paschen lines (either Pa or
Pa), providing simple, analytical classification criteria. We apply
these diagnostics to a sample of 64 star-forming galaxies and AGNs at 0 < z <
1, and 65 sources at 1 < z < 3 recently observed with JWST-NIRSpec in CEERS. We
find that the classification inferred from the near-infrared is broadly
consistent with the optical one based on the BPT and the [SII]/H ratio.
However, in the near-infrared, we find more AGNs than in the
optical (13 instead of 8), with 5 sources classified as 'hidden' AGNs, showing
a larger AGN contribution at longer wavelengths, possibly due to the presence
of optically thick dust. The diagnostics we present provide a promising tool to
find and characterize AGNs from z=0 to z=3 with low and medium-resolution
near-IR spectrographs in future surveys.Comment: Paper accepted for publication in A&A on 05/09/2023. Three public
Github repositories include: (1) a table with emission line measurements for
the paper sample : https://github.com/Anthony96/Line_measurements_nearIR ,
Cloudy emission line predictions for star-forming galaxies and AGN models :
https://github.com/Anthony96/star-forming_models ,
https://github.com/Anthony96/AGN_model
Spectroscopic verification of very luminous galaxy candidates in the early universe
During the first 500 million years of cosmic history, the first stars and
galaxies formed and seeded the cosmos with heavy elements. These early galaxies
illuminated the transition from the cosmic "dark ages" to the reionization of
the intergalactic medium. This transitional period has been largely
inaccessible to direct observation until the recent commissioning of JWST,
which has extended our observational reach into that epoch. Excitingly, the
first JWST science observations uncovered a surprisingly high abundance of
early star-forming galaxies. However, the distances (redshifts) of these
galaxies were, by necessity, estimated from multi-band photometry. Photometric
redshifts, while generally robust, can suffer from uncertainties and/or
degeneracies. Spectroscopic measurements of the precise redshifts are required
to validate these sources and to reliably quantify their space densities,
stellar masses, and star formation rates, which provide powerful constraints on
galaxy formation models and cosmology. Here we present the results of JWST
follow-up spectroscopy of a small sample of galaxies suspected to be amongst
the most distant yet observed. We confirm redshifts z > 10 for two galaxies,
including one of the first bright JWST-discovered candidates with z = 11.4, and
show that another galaxy with suggested z ~ 16 instead has z = 4.9, with strong
emission lines that mimic the expected colors of more distant objects. These
results reinforce the evidence for the rapid production of luminous galaxies in
the very young Universe, while also highlighting the necessity of spectroscopic
verification for remarkable candidates.Comment: Submitted to Natur
CEERS Spectroscopic Confirmation of NIRCam-Selected z > 8 Galaxy Candidates with JWST/NIRSpec: Initial Characterization of their Properties
We present JWST NIRSpec spectroscopy for 11 galaxy candidates with
photometric redshifts of and newly
identified in NIRCam images in the Cosmic Evolution Early Release Science
(CEERS) Survey. We confirm emission line redshifts for 7 galaxies at
using spectra at m either with the NIRSpec prism or
its three medium resolution gratings. For photometric candidates, we
achieve a high confirmation rate of 90\%, which validates the classical
dropout selection from NIRCam photometry. No robust emission lines are
identified in three galaxy candidates at , where the strong [OIII] and
H lines would be redshifted beyond the wavelength range observed by
NIRSpec, and the Lyman- continuum break is not detected with the
current sensitivity. Compared with HST-selected bright galaxies
() that are similarly spectroscopically confirmed at
, these NIRCam-selected galaxies are characterized by lower star
formation rates (SFR~yr) and lower stellar masses
(), but with higher [OIII]+H equivalent widths
(1100), and elevated production efficiency of ionizing photons
() induced by young stellar
populations (~Myrs) accounting for of the galaxy mass,
highlighting the key contribution of faint galaxies to cosmic reionization.
Taking advantage of the homogeneous selection and sensitivity, we also
investigate metallicity and ISM conditions with empirical calibrations using
the [OIII]/H ratio. We find that galaxies at have higher SFRs
and lower metallicities than galaxies at similar stellar masses at ,
which is generally consistent with the current galaxy formation and evolution
models.Comment: 21 pages, 11 figures, 2 tables. Submitted to ApJL Focus Issu
Spectroscopic confirmation of CEERS NIRCam-selected galaxies at
We present JWST/NIRSpec prism spectroscopy of seven galaxies selected from
the Cosmic Evolution Early Release Science Survey (CEERS) NIRCam imaging with
photometric redshifts z_phot>8. We measure emission line redshifts of z=7.65
and 8.64 for two galaxies, and z=9.77(+0.37,-0.29) and 10.01(+0.14,-0.19) for
two others via the detection of continuum breaks consistent with Lyman-alpha
opacity from a mostly neutral intergalactic medium. The presence (absense) of
strong breaks (strong emission lines) give high confidence that these two
galaxies are at z>9.6, but the break-derived redshifts have large uncertainties
given the low spectral resolution and relatively low signal-to-noise of the
CEERS NIRSpec prism data. The two z~10 sources are relatively luminous
(M_UV<-20), with blue continua (-2.3<beta<-1.9) and low dust attenuation
(A_V=0.15(+0.3,-0.1)); and at least one of them has high stellar mass for a
galaxy at that redshift (log(M_*/M_sol)=9.3(+0.2,-0.3)). Considered together
with spectroscopic observations of other CEERS NIRCam-selected high-z galaxy
candidates in the literature, we find a high rate of redshift confirmation and
low rate of confirmed interlopers (8.3%). Ten out of 34 z>8 candidates with
CEERS NIRSpec spectroscopy do not have secure redshifts, but the absence of
emission lines in their spectra is consistent with redshifts z>9.6. We find
that z>8 photometric redshifts are generally in agreement (within
uncertainties) with the spectroscopic values. However, the photometric
redshifts tend to be slightly overestimated (average Delta(z)=0.50+/-0.12),
suggesting that current templates do not fully describe the spectra of very
high-z sources. Overall, our results solidifies photometric evidence for a high
space density of bright galaxies at z>8 compared to theoretical model
predictions, and further disfavors an accelerated decline in the integrated UV
luminosity density at z>8.Comment: Submitted to ApJL. 24 pages, 9 figures, 7 tables. File with Table 6
included in source .tar fil
The Physical Conditions of Emission-Line Galaxies at Cosmic Dawn from JWST/NIRSpec Spectroscopy in the SMACS 0723 Early Release Observations
We present rest-frame optical emission-line flux ratio measurements for five
galaxies observed by the JWST Near-Infared Spectrograph (NIRSpec) in the
SMACS 0723 Early Release Observations. We add several quality-control and
post-processing steps to the NIRSpec pipeline reduction products in order to
ensure reliable relative flux calibration of emission lines that are closely
separated in wavelength, despite the uncertain \textit{absolute}
spectrophotometry of the current version of the reductions. Compared to
galaxies in the literature, the galaxies have similar
[OIII]5008/H ratios, similar [OIII]4364/H
ratios, and higher (0.5 dex) [NeIII]3870/[OII]3728
ratios. We compare the observations to MAPPINGS V photoionization models and
find that the measured [NeIII]3870/[OII]3728,
[OIII]4364/H, and [OIII]5008/H emission-line
ratios are consistent with an interstellar medium that has very high ionization
(, units of cm~s), low metallicity (), and very high pressure (, units of
cm). The combination of [OIII]4364/H and
[OIII](4960+5008)/H line ratios indicate very high electron
temperatures of , further implying metallicities of
with the application of low-redshift calibrations for
``-based'' metallicities. These observations represent a tantalizing new
view of the physical conditions of the interstellar medium in galaxies at
cosmic dawn.Comment: Accepted for publication in AAS Journals. 14 pages, 6 figures, 3
table
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