28 research outputs found
AGN Selection and Demographics: A New Age with JWST/MIRI
Understanding the co-evolution of supermassive black holes (SMBHs) and their
host systems requires a comprehensive census of active galactic nuclei (AGN)
behavior across a wide range of redshift, luminosity, obscuration level and
galaxy properties. We report significant progress with JWST towards this goal
from the Systematic Mid-infrared Instrument Legacy Extragalactic Survey
(SMILES). Based on comprehensive SED analysis of 3273 MIRI-detected sources, we
identify 217 AGN candidates over a survey area of 34 arcmin,
including a primary sample of 111 AGNs in normal massive galaxies
() at 0--4, an extended sample of 86 AGN {\it
candidates} in low-mass galaxies () and a high-
sample of 20 AGN {\it candidates} at 4--8.4. Notably, about 80\% of our
MIRI-selected AGN candidates are new discoveries despite the extensive pre-JWST
AGN searches. Even among the massive galaxies where the previous AGN search is
believed to be thorough, 34\% of the MIRI AGN identifications are new,
highlighting the impact of obscuration on previous selections. By combining our
results with the efforts at other wavelengths, we build the most complete AGN
sample to date and examine the relative performance of different selection
techniques. We find the obscured AGN fraction increases from to and then drops towards higher
luminosity. Additionally, the obscured AGN fraction gradually increases from
to with most high- AGNs obscured. We discuss how AGN
obscuration, intrinsic SED variations, galaxy contamination, survey depth and
selection techniques complicate the construction of a complete AGN sample.Comment: 32 pages, 21 figures, submitted to Ap
JADES Imaging of GN-z11: Revealing the Morphology and Environment of a Luminous Galaxy 430 Myr After the Big Bang
We present JWST NIRCam 9-band near-infrared imaging of the luminous
galaxy GN-z11 from the JWST Advanced Deep Extragalactic Survey (JADES) of the
GOODS-N field. We find a spectral energy distribution (SED) entirely consistent
with the expected form of a high-redshift galaxy: a clear blue continuum from
1.5 to 4 microns with a complete dropout in F115W. The core of GN-z11 is
extremely compact in JWST imaging. We analyze the image with a two-component
model, using a point source and a S\'{e}rsic profile that fits to a half-light
radius of 200 pc and an index . We find a low-surface brightness haze
about to the northeast of the galaxy, which is most likely a foreground
object but might be a more extended component of GN-z11. At a spectroscopic
redshift of 10.60 (Bunker et al. 2023), the comparison of the NIRCam F410M and
F444W images spans the Balmer jump. From population synthesis modeling, here
assuming no light from an active galactic nucleus, we reproduce the SED of
GN-z11, finding a stellar mass of , a star-formation
rate of and a young stellar age of
. As massive galaxies at high redshift are likely to be
highly clustered, we search for faint neighbors of GN-z11, finding 9 galaxies
out to 5 comoving Mpc transverse with photometric redshifts consistent
with , and a 10 more tentative dropout only away.Comment: Submitted to ApJ; 18 pages, 8 figures; comments welcom
The JADES Origins Field: A New JWST Deep Field in the JADES Second NIRCam Data Release
We summarize the properties and initial data release of the JADES Origins
Field (JOF), which will soon be the deepest imaging field yet observed with the
James Webb Space Telescope (JWST). This field falls within the GOODS-S region
about 8' south-west of the Hubble Ultra Deep Field (HUDF), where it was formed
initially in Cycle 1 as a parallel field of HUDF spectroscopic observations
within the JWST Advanced Deep Extragalactic Survey (JADES). This imaging will
be greatly extended in Cycle 2 program 3215, which will observe the JOF for 5
days in six medium-band filters, seeking robust candidates for z>15 galaxies.
This program will also include ultra-deep parallel NIRSpec spectroscopy (up to
104 hours on-source, summing over the dispersion modes) on the HUDF. Cycle 3
observations from program 4540 will add 20 hours of NIRCam slitless
spectroscopy to the JOF. With these three campaigns, the JOF will be observed
for 380 open-shutter hours with NIRCam using 15 imaging filters and 2 grism
bandpasses. Further, parts of the JOF have deep 43 hr MIRI observations in
F770W. Taken together, the JOF will soon be one of the most compelling deep
fields available with JWST and a powerful window into the early Universe. This
paper presents the second data release from JADES, featuring the imaging and
catalogs from the year 1 JOF observations.Comment: Submitted to ApJ Supplement. Images and catalogs are available at
https://archive.stsci.edu/hlsp/jades . A FITSmap portal to view the images is
at https://jades.idies.jhu.ed
JADES Initial Data Release for the Hubble Ultra Deep Field: Revealing the Faint Infrared Sky with Deep JWST NIRCam Imaging
JWST has revolutionized the field of extragalactic astronomy with its
sensitive and high-resolution infrared view of the distant universe. Adding to
the new legacy of JWST observations, we present the first NIRCam imaging data
release from the JWST Advanced Deep Extragalactic Survey (JADES) providing 9
filters of infrared imaging of 25 arcmin covering the Hubble Ultra
Deep Field and portions of Great Observatories Origins Deep Survey (GOODS)
South. Utilizing 87 on-sky dual-filter hours of exposure time, these images
reveal the deepest ever near-infrared view of this iconic field. We supply
carefully constructed 9-band mosaics of the JADES bands, as well as matching
reductions of 5 additional bands from the JWST Extragalactic Medium-band Survey
(JEMS). Combining with existing HST imaging, we provide 23-band space-based
photometric catalogs and photometric redshifts for sources. To
promote broad engagement with the JADES survey, we have created an interactive
{\tt FitsMap} website to provide an interface for professional researchers and
the public to experience these JWST datasets. Combined with the first JADES
NIRSpec data release, these public JADES imaging and spectroscopic datasets
provide a new foundation for discoveries of the infrared universe by the
worldwide scientific community.Comment: Several figures were modified to use better line styles. A brief
comparison to IRAC Channel 1 photometry was added along with a few other
clarifications. Paper has been accepted for publication in ApJ
JADES Initial Data Release for the Hubble Ultra Deep Field: Revealing the Faint Infrared Sky with Deep JWST NIRCam Imaging
© 2023. The Author(s). Published by the American Astronomical Society. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY), https://creativecommons.org/licenses/by/4.0/JWST has revolutionized the field of extragalactic astronomy with its sensitive and high-resolution infrared view of the distant Universe. Adding to the new legacy of JWST observations, we present the first NIRCam imaging data release from the JWST Advanced Deep Extragalactic Survey (JADES), providing nine filters of infrared imaging of ∼25 arcmin2 covering the Hubble Ultra Deep Field and portions of Great Observatories Origins Deep Survey South. Utilizing 87 on-sky dual-filter hours of exposure time, these images reveal the deepest ever near-infrared view of this iconic field. We supply carefully constructed nine-band mosaics of the JADES bands, as well as matching reductions of five additional bands from the JWST Extragalactic Medium-band Survey. Combining with existing Hubble Space Telescope imaging, we provide 23-band space-based photometric catalogs and photometric redshifts for ≈47,500 sources. To promote broad engagement with JADES, we have created an interactive FitsMap website to provide an interface for professional researchers and the public to experience these JWST data sets. Combined with the first JADES NIRSpec data release, these public JADES imaging and spectroscopic data sets provide a new foundation for discoveries of the infrared Universe by the worldwide scientific community.Peer reviewe
JADES NIRSpec Spectroscopy of GN-z11: Lyman- emission and possible enhanced nitrogen abundance in a luminous galaxy
We present JADES JWST/NIRSpec spectroscopy of GN-z11, the most luminous
candidate Lyman break galaxy in the GOODS-North field with
. We derive a redshift of (lower than previous
determinations) based on multiple emission lines in our low and medium
resolution spectra over m. We significantly detect the continuum
and measure a blue rest-UV spectral slope of . Remarkably, we see
spatially-extended Lyman- in emission (despite the highly-neutral IGM
expected at this early epoch), offset 555 km/s redward of the systemic
redshift. From our measurements of collisionally-excited lines of both low- and
high-ionization (including [O II] , [Ne III] and C
III] ) we infer a high ionization parameter (). We
detect the rarely-seen N IV] and N III] lines in
both our low and medium resolution spectra, with other high ionization lines
seen in low resolution spectrum such as He II (blended with O III]) and C IV
(with a possible P-Cygni profile). Based on the observed rest-UV line ratios,
we cannot conclusively rule out photoionization from AGN. The high C III]/He II
ratios, however, suggest a likely star-formation explanation. If the observed
emission lines are powered by star formation, then the strong N III]
observed may imply an unusually high abundance. Balmer
emission lines (H, H) are also detected, and if powered by star
formation rather than an AGN we infer a star formation rate of (depending on the IMF) and low dust attenuation. Our
NIRSpec spectroscopy confirms that GN-z11 is a remarkable galaxy with extreme
properties seen 430 Myr after the Big Bang.Comment: Submitted to Astronomy & Astrophysics, 14 pages, 9 figure
The James Webb Space Telescope Mission
Twenty-six years ago a small committee report, building on earlier studies,
expounded a compelling and poetic vision for the future of astronomy, calling
for an infrared-optimized space telescope with an aperture of at least .
With the support of their governments in the US, Europe, and Canada, 20,000
people realized that vision as the James Webb Space Telescope. A
generation of astronomers will celebrate their accomplishments for the life of
the mission, potentially as long as 20 years, and beyond. This report and the
scientific discoveries that follow are extended thank-you notes to the 20,000
team members. The telescope is working perfectly, with much better image
quality than expected. In this and accompanying papers, we give a brief
history, describe the observatory, outline its objectives and current observing
program, and discuss the inventions and people who made it possible. We cite
detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space
Telescope Overview, 29 pages, 4 figure
Structural studies of Immune Mapped Protein 1 (IMP1) homologues in apicomplexan parasites
Apicomplexan parasites are responsible for causing a number of diseases in humans and animals. Toxoplasma gondii is known to cause toxoplasmosis in humans, Eimeria tenella is known to cause coccidiosis in chickens and Plasmodium falciparum is known to cause malaria in humans. These parasites place a huge burden on global health and on the global economy. Current methods of treatment are losing effectiveness, raising the need for new ways to combat these diseases. Identifying vaccine candidates against apicomplexan parasites has been the focus of recent research. Immune Mapped Protein 1 (IMP1) is a novel antigenic protein which was first identified in Eimeria maxima. Recent research has shown that immunisation with IMP1 raises immunity against the parasite in a species specific manner. However, the structure and function of IMP1 is not known.
Here we report the structure of the IMP homologue from Plasmodium falciparum (PfIMP2) solved using solution state Nuclear Magnetic Resonance (NMR). The structure of PfIMP2 has revealed that IMP homologues have a conserved C-terminal IMP domain. Recent research has also revealed that the IMP domain is the immune-dominant region in the IMP homologues. We also report that there are two classes of IMP homologues within apicomplexans. This redundancy of the protein within the parasites suggests that IMP homologues play an important role within the parasite. In vitro experiments performed to gain some insight on the functional role played by IMP proteins within the parasites are also reported. Although the function of the IMP homologues is yet to be deduced, the immunogenic nature of these homologues makes them interesting candidates to study.Open Acces
Structural basis of phosphatidic acid sensing by APH in apicomplexan parasites
Plasmodium falciparum and Toxoplasma gondii are obligate intracellular parasites that belong to the phylum of Apicomplexa and cause major human diseases. Their access to an intracellular lifestyle is reliant on the coordinated release of proteins from the specialized apical organelles called micronemes and rhoptries. A specific phosphatidic acid effector, the acylated pleckstrin homology domain-containing protein (APH) plays a central role in microneme exocytosis and thus is essential for motility, cell entry, and egress. TgAPH is acylated on the surface of the micronemes and recruited to phosphatidic acid (PA)-enriched membranes. Here, we dissect the atomic details of APH PA-sensing hub and its functional interaction with phospholipid membranes. We unravel the key determinant of PA recognition for the first time and show that APH inserts into and clusters multiple phosphate head-groups at the bilayer binding surface