Near-infrared Narrow-band Imaging Research Articles

The Galaxy Environment of Extremely Massive Quasars. I. An Overdensity of Hα Emitters at z = 1.47

Abstract We measure a strong excess in the galaxy number density around PG 1630+377, an extremely massive (M BH ≃ 109.7 M ⊙) quasar at z = 1.475, using near-infrared narrowband imaging. We identify 79 narrow H-band excess objects in a 525 arcmin2 area including the vicinity and surroundings of the quasar. These sources are likely Hα line emitting, star-forming galaxies at z ≈ 1.47. We detect a δ = 6.6 ± 2.7 overdensity of narrow H-band excess objects located at a projected distance ≈2.1 Mpc northeast of the quasar, which is the densest region in the target area. The overdensity is present in BzK color-selected galaxies, while a previously reported overdensity in the immediate vicinity of PG 1630+377 is not, and yet appears as a group-like structure. These megaparsec-scale environments are estimated to merge into a ≃1014.7 M ⊙ cluster at present. Our results support the view that extremely massive black holes form and grow in group-scale environments and later incorporate into a galaxy cluster.

Wide field-of-view study of the Eagle Nebula with the Fourier transform imaging spectrograph SITELLE at CFHT

Context. We present the very first wide-field, 11′ by 11′, optical spectral mapping of M 16, one of the most famous star-forming regions in the Galaxy. The data were acquired with the new imaging Fourier transform spectrograph SITELLE mounted on the Canada-France-Hawaii Telescope (CFHT). We obtained three spectral cubes with a resolving power of 10 000 (SN1 filter), 1500 (SN2 filter) and 600 (SN3 filter), centered on the iconic Pillars of Creation and the HH 216 flow, covering the main optical nebular emission lines, namely [O II]λ3726,29 (SN1), Hβ, [O III]λ4959,5007 (SN2), [N II]λ6548,84, Hα, and [S II]λ6717,31 (SN3). Aims. We validate the performance, calibration, and data reduction of SITELLE, and analyze the structures in the large field-of-view in terms of their kinematics and nebular emission. Methods. We compared the SITELLE data to MUSE integral field observations and other spectroscopic and narrow-band imaging data to validate the performance of SITELLE. We computed gas-phase metallicities via the strong-line method, performed a pixel-by-pixel fit to the main emission lines to derive kinematics of the ionized gas, computed the mass-loss rate of the Eastern pillar (also known as the Spire), and combined the SITELLE data with near-infrared narrow-band imaging to characterize the HH 216 flow. Results. The comparison with previously published fluxes demonstrates very good agreement. We disentangle the dependence of the gas-phase metallicities (derived via abundance-tracing line ratios) on the degree of ionization and obtain metallicities that are in excellent agreement with the literature. We confirm the bipolar structure of HH 216, find evidence for episodic accretion from the source of the flow, and identify its likely driving source. We compute the mass-loss rate Ṁ of the Spire pillar on the East side of the H II region and find excellent agreement with the correlation between the mass-loss rate and the ionizing photon flux from the nearby cluster NGC 6611.

PHOTOMETRIC MEASUREMENTS OF H2O ICE CRYSTALLINITY ON TRANS-NEPTUNIAN OBJECTS*

ABSTRACT We present a measurement of H2O ice crystallinity on the surface of trans-neptunian objects with near-infrared narrow-band imaging. The newly developed photometric technique allows us to efficiently determine the strength of a 1.65 μm absorption feature in crystalline H2O ice. Our data for three large objects—Haumea, Quaoar, and Orcus—which are known to contain crystalline H2O ice on the surfaces, show a reasonable result with high fractions of the crystalline phase. It can also be pointed out that if the grain size of H2O ice is larger than ∼20 μm, the crystallinities of these objects are obviously below 1.0, which suggests the presence of the amorphous phase. In particular, Orcus exhibits a high abundance of amorphous H2O ice compared to Haumea and Quaoar, possibly indicating a correlation between the bulk density of the bodies and the degree of surface crystallization. We also found the presence of crystalline H2O ice on Typhon and 2008 AP129, both of which are smaller than the minimum size limit for inducing cryovolcanism as well as a transition from amorphous to crystalline phase through thermal evolution due to the decay of long-lived isotopes.

Coaxial rings and H2 knots in Hubble 12

Hubble 12 (Hb 12) is a young planetary nebula (PN) exhibiting nested shells. We present new near-infrared narrow-band imaging observations of Hb 12 using the Canada-France- Hawaii Telescope (CFHT). A number of co-axial rings aligned with the bipolar lobes and two pairs of separate H2 knots with different orientations are detected.

Narrow band imaging of squamous cell carcinoma tumors using topically delivered anti‐EGFR antibody conjugated gold nanorods

Nanoparticles have recently gained interest as exogenous contrast agents in a variety of biomedical applications related to cancer detection and treatment. The objective of this study was to determine the potential of topically administered antibody conjugated gold nanorods (GNRs) for imaging squamous cell carcinomas (SCCs) of the skin using near-infrared narrowband imaging (NBI). Near-infrared (NIR) NBI images narrow wavelength bands to enhance contrast from plasmonic particles in a wide field portable and noncontact device that is clinically compatible for real-time tumor imaging and tumor margin demarcation. We conjugated GNRs to Cetuximab, a clinically approved humanized antibody that targets the epidermal growth factor receptor (EGFR), which is overexpressed on the surface of many tumor cells, especially SCCs. We excised subcutaneous xenografts of SCCs (A431) from Swiss nu/nu mice and divided the tumors into two groups: (1) the targeted group (Cetuximab conjugated GNRs) and (2) the control group (polyethylene glycol-conjugated GNRs). After topical application of particles and incubation for 30 minutes, the tumors were washed and imaged using NBI. In addition, we performed two-photon imaging to quantify the binding of EGFR targeted GNRs in tumors and their depth profile. The NBI images showed a visual increase in contrast from tumors after topical administration of targeted GNR. Targeted GNR tumors showed increased contrast compared to tumors administered with the control GNR. There was a statistically significant increase in mean pixel intensity (∼2.5×) from targeted GNR tumors (n = 6). Two-photon microscopy images of targeted GNRs confirmed their binding affinity to the EGF receptors over expressed in the A431 tumors. We have demonstrated that a topical application of gold nanorods targeted specifically to tumor growth factor receptors results in a significantly higher image contrast compared to nontargeted gold nanorods. These results demonstrate the feasibility of near-infrared NBI to image and demarcate tumor margins during surgical resection using topical administration of targeted GNR.

Searching for emission line and OB stars in Cl 1806-20 using a NIR narrow-band technique

AbstractWe survey the environment of Cl 1806-20 using near-infrared narrow-band imaging to search for Brγ features indicative of evolved massive stars. Using this technique, we successfully detect previously identified massive stars in the cluster. We detect no new emission line stars, establishing a firm upper limit on the number of Wolf Rayets and Luminous Blue Variables; however, we do find several candidate OB supergiants, which likely represent the bulk of the heretofore undiscovered massive star population.

Near-infrared narrow-band imaging of gold/silica nanoshells in tumors.

Gold nanoshells (GNS) are a new class of nanoparticles that can be optically tuned to scatter or absorb light from the near-ultraviolet to near-infrared (NIR) region by varying the core (dielectric silica)/shell (gold) ratio. In addition to spectral tunability, GNS are inert and bioconjugatable, making them potential labels for in vivo imaging and therapy of tumors. We report the use of GNS as exogenous contrast agents for enhanced visualization of tumors using narrow-band imaging (NBI). NBI takes advantage of the strong NIR absorption of GNS to distinguish between blood and nanoshells in the tumor by imaging in narrow wavelength bands in the visible and NIR, respectively. Using tissue-simulating phantoms, we determined the optimum wavelengths to enhance contrast between blood and GNS. We then used the optimum wavelengths for ex vivo imaging of tumors extracted from human colon cancer xenograft bearing mice injected with GNS. Systemically delivered GNS accumulated passively in tumor xenografts by the enhanced permeability and retention (EPR) effect. Ex vivo NBI of tumor xenografts demonstrated heterogeneous distribution of GNS with a clear distinction from the tumor vasculature. The results of this study demonstrate the feasibility of using GNS as contrast agents to visualize tumors using NBI.

A Near‐Infrared and X‐Ray Study of W49 B: A Wind Cavity Explosion

We present near-infrared narrowband images of the supernova remnant W49 B, taken with the WIRC instrument on the Hale 200 inch (5 m) telescope on Mount Palomar. The 1.64 μm [Fe II] image reveals a barrel-shaped structure with coaxial rings, which is suggestive of bipolar wind structures surrounding massive stars. The 2.12 μm shocked molecular hydrogen image extends 1.9 pc outside of the [Fe II] emission to the southeast. We also present archival Chandra data, which show an X-ray jetlike structure along the axis of the [Fe II] barrel, flaring at each end. Fitting single-temperature X-ray emission models reveals an enhancement of heavy elements, with particularly high abundances of hot Fe and Ni, and relatively metal-rich core and jet regions. We interpret these findings as evidence that W49 B originated inside a wind-blown bubble (R ~ 5 pc) inside a dense molecular cloud. This suggests that W49 B's progenitor was a supermassive star that could significantly shape its surrounding environment. We also suggest two interpretations for the jet morphology, abundance variations, and molecular hydrogen emission: (1) the explosion may have been jet driven, interacting with the molecular cavity (i.e., a gamma-ray burst); or (2) the explosion could have been a traditional supernova, with the jet structure being the result of interactions between the shock and an enriched interstellar cloud.

G76.188+0.098: a newly born massive binary star

Context. We present observations of G76.188+0.098, an object classified in the literature as an ultracompact HII region (UCHIIR) based on its far-infrared and radio continuum characteristics. Aims. To investigate the nature of this object on the basis of the combination of radio observations existing in the literature and the new observations in the near-infrared presented here, with particular attention to the direct detection of the central ionizing source. Methods. Near-infrared narrow-band imaging and low resolution spectroscopy in the 2 μ m region. Results. The new observations clearly reveal the central source, which turns out to be a resolved binary system obscured by $A_K \simeq 4.4$ mag. A general agreement is found between the morphology of the region as outlined by narrow-band, near-infrared imaging, and existing VLA radio continuum maps. Indirect evidence based on the low HeI (2.058 μ m) / Br γ intensity ratio of the compact nebula suggests that the binary system is composed of two stars with spectral types O9 and B0 at a distance of ~2.4 kpc, somewhat closer to the Sun than commonly assumed in the literature. Conclusions. The size of the central cavity of the compact nebula, the low electron densities derived from radio continuum measurements, and the moderate extinction towards the central source by UCHIIR standards suggest that G76.188+0.098 is a very young massive binary observed near the end of the embedded, ultracompact phase, adding one example to the rare cases in which the central source of an ultracompact HII region is detected.

Near‐Infrared [Fe ii ] Emission in Starburst Galaxies. I. Measured Properties

We used the near-infrared [Fe II] emission line signature to detect supernova remnants (SNRs) in the nearby starburst galaxies NGC 1569, NGC 3738, and NGC 5253. The near-infrared narrowband imaging program has led to the detection of 10 SNR candidates in NGC 1569, 7 in NGC 5253, and none in NGC 3738. The luminosity of the SNRs candidates varies from 72 to 780 L☉ and from 69 to 331 L☉ for NGC 1569 and NGC 5253, respectively. Also, a spatially extended component to the [Fe II] line emission is observed in NGC 1569 and NGC 5253. This component dominates the integrated [Fe II] luminosity in both galaxies, the compact sources accounting for 14% and 7% of the total [Fe II] luminosity of NGC 1569 and NGC 5253, respectively.

Hα‐derived Star Formation Rates for thez= 0.84 Galaxy Cluster Cl J0023+0423B

We present Hα-derived star formation rates (SFRs) for the galaxy cluster Cl J0023+0423B at z = 0.845. Our 3 σ flux limits correspond to an SFR of 0.24 h M☉ yr-1, and our minimum reliable Hα + [N ] equivalent width is greater than 10 A, demonstrating that near-infrared narrowband imaging can sample the star-forming galaxy population in distant clusters. Comparison with spectroscopy shows that the number of false detections is low (9% ± 6%) and that our Hα equivalent widths are correlated with spectroscopically determined [O II] equivalent widths. A magnitude-limited spectroscopic survey conducted over the same area missed 70% of the star-forming galaxies and 65% of the integrated star formation. Using Hubble Space Telescope Wide Field Planetary Camera 2 Archive images, we fit Sersic profiles to all galaxies with significant narrowband equivalent widths and find that equivalent width decreases as the steepness of galaxy profile increases. We find no significant population of early-type galaxies with ongoing star formation. The integrated SFR per cluster mass of Cl J0023+0423B is a factor of 10 higher than that of the three z ~ 0.2 clusters in the literature with available Hα observations. A larger sample of z ~ 0.8 clusters spanning a range of cluster masses is needed to determine whether this variation is due to a difference in cluster mass or redshift.

Results from a near infrared search for emission-line stars in the Inner Galaxy: Spectra of new Wolf-Rayet stars

We present follow-up spectroscopy of emission line candidates detected on near-infrared narrow band images in the inner Galaxy (Homeier et al. 2003). The filters are optimized for the detection of Wolf-Rayet stars and other objects which exhibit emission-lines in the 2 µm region. Approximately three square degrees along the Galactic plane have been analyzed in seven narrow-filters (four emission-lines and three continuum). We have discovered 4 new Wolf-Rayet stars and present coordinates, finding charts, and K-band spectra.

Three Emission‐Line Galaxies atz ∼ 2.4

We present Keck near-infrared and WIYN (Wisconsin-Indiana-Yale NOAO) optical photometry of a sample of galaxies detected by near-infrared narrowband imaging in the fields of quasar metal absorption line systems at z ~ 2.4. Wide separations (0.6-1.6 h-1 Mpc) from the quasars indicate that they are not directly responsible for the absorption systems. From the color excess of the galaxies we derived line fluxes, star formation rates, and equivalent widths. The data are consistent with one source having an active nucleus and two sources containing regions of star formation. The blue (R-K) colors for the sources suggest relatively lower dust content. We discuss possible projects using current wide-field infrared instruments, which can cover an order of magnitude greater area with modest allocations of telescope time.

A Morphological Study of Infrared Line Emission in Compact Star-Forming Regions

Near-infrared broadband and narrowband images are presented for 11 Galactic star-forming regions. Data were taken using the infrared camera on the Mount Palomar 60 inch (1.5 m) telescope with the broadband filters J, H, and K and with narrowband filters centered on H2 and Brγ. The morphologies of these regions are compared with ultraviolet fluorescence and shock front models of line emission. We find that the majority of these star-forming regions can be described by ultraviolet fluorescence.

Investigating the near-IR properties of PN: Deep imaging of molecular hydrogen emission

We present the first results of a deep near-infrared narrowband imaging study of several planetary nebulae. The data were acquired using the University of Hawaii 2.2m telescope on Mauna Kea and the “QUIRC” 1024 × 1024 array camera. With these sensitive high spatial resolution imaging data, we are able to explore in detail where H2 is found relative to the ionized region in planetary nebulae at various stages of evolution (See Figure 1, for an example). The objects were selected from previous studies to have evidence for extended emission from H2, and they are at several differing phases of central star evolution. The presence of molecules in the UV–flooded environment of a planetary nebula cannot be explained without highly non-spherical geometries and high densities, or clumping. Although there can be an ambiguity in the excitation mechanism (UV photons or shocks), the location of H2 emission identifies regions of the nebula with sufficient dust shielding and density for the survival of molecular species. The emission morphology also provides information that helps identify which excitation mechanism is most likely. When combined with data provided by other molecular studies, we can examine how the photodissociation region evolves through the circumstellar envelope as the planetary nebula tracks across the top of the HR diagram. We can also consider how morphological evolution of the nebula, through interacting winds and shocks, might provide the conditions necessary for molecular survival.

Investigating the Near-Infrared Properties of Planetary Nebulae. I. Narrowband Images

We present the results of a near-infrared narrowband imaging survey of planetary nebulae. Objects were selected in a way that complements similar surveys done at visible and near-infrared wavelengths. No new detections of molecular hydrogen emission were made. The H2 is frequently found to be extended, except in young, visibly compact objects. Our results are consistent with the already determined correlation of H2 emission with planetary nebula morphological type. Filamentary and other kinds of structures are clearly resolved in many nebulae.