arXiv subjects

Matthew A. Bershady

Publications and source records attributed to Matthew A. Bershady.

At least 19 recordsLinked to original sources

arXiv2026

A Slit Mask Integral Field Unit for the Robert Stobie Spectrograph on the Southern African Large Telescope: I. Instrument Development

Integral field spectroscopy (IFS) has been added as a new observation mode to the Robert Stobie Spectrograph (RSS), the workhorse multi-mode instrument on the Southern African Large Telescope. RSS operates as an imaging spectrograph covering 320-900 nm with a spectral resolution--slit-width product of 6600 arcsec. Using fiber optics and prismatic fold mirrors, we have been able to construct compact integral field units (IFUs) that fit within the same volume as the long-slit cassettes (134 mm x 130 mm x 8 mm). These `slit mask' IFUs (SMIs) direct the telescope beam into a 2D sky-facing fiber array routed in the focal plane dimension into an 8$\arcmin$ 1D pseudo-slit, with fiber output redirected back into the spectrograph collimator. The first completed unit, SMI-200, features 303 object fibers and 24 sky fibers, providing a spatial resolution of 0.8$\arcsec$ (200 $\upmu$m core diameter) over a field of view (FOV) of 22.5$\arcsec$ x 17.6$\arcsec$. This paper describes the specific design considerations and design and fabrication strategies to maximize performance and minimize risk during construction, given the demanding and highly constrained cassette geometry. We also detail mapping and laboratory characterization of the IFU. Laboratory measurements demonstrate a total throughput of 77\%, but an effective throughput of only 55-60\% within the RSS collimator acceptance beam of f/4.2 due to losses dominated by focal ratio degradation (FRD) induced by sharp bend radii imposed by the tight cassette volume.

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arXiv2024

On the role of non-circular motions in MaNGA galaxies I: global properties

Non-circular (NC) motions represent the imprints of non-axisymmetric structures in galaxies, providing opportunities to study the physical properties of gas departing from circular rotation. In this work, we have conducted a systematic study of the non-circular motions in a sample of 1624 gas-rich disk galaxies from the MaNGA MPL-11. By using the H$α$ velocity as a tracer of the disk rotation, we find indications that the amplitude of the non-circular motions is related to the stellar mass, with the low mass and late-type galaxies the most affected. In our sample, we find ratios of non-circular to circular rotation ranging from 5% to 20%. By implementing harmonic models to include NC motions associated with spiral arms and stellar bars, we find that the rotational curves traced with H$α$ are barely affected by the NC induced by these structures. Consequently, in our sample, we do not find evidence that NC motions contribute to the scatter of the stellar Tully-Fisher relation. Our results suggest that non-circular motions might have a more localized effect in galaxies rather than a global one.

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arXiv2024

Light scrambling and focal ratio degradation of thin multimode fibers with different core geometries

The performance of fiber-fed astronomical spectrographs is highly influenced by the properties of fibers. The near-field and far-field scrambling characteristics have a profound impact on the line spread function (LSF) of the spectra. Focal ratio degradation (FRD) influences the output beam size, thereby affecting the throughput, as well as the size of the collimator and dispersion elements. While previous research has indicated that these properties depend on the shape of the fiber core and showed that non-circular core fibers can yield uniform near-field scrambling, the result remains inconclusive for far-field. In this study, we investigate the near-field and far-field scrambling properties, along with the FRD, of 50-micron core fibers with different core geometries. We find that in addition to excellent near-field scrambling, octagonal-core fibers can also produce more uniform far-field output when compared to circular-core fibers. They also have less FRD effect when being fed with a f/3 beam.

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arXiv2024

The Strength of Bisymmetric Modes in SDSS-IV/MaNGA Barred Galaxy Kinematics

The SDSS-IV/MaNGA Survey data provide an unprecedented opportunity to study the internal motions of galaxies and, in particular, represent the largest sample of barred galaxy kinematic maps obtained to date. We present results from Nirvana, our non-axisymmetric kinematic modeling code built with a physically-motivated Bayesian forward modeling approach, which decomposes MaNGA velocity fields into first- and second-order radial and tangential rotational modes in a generalized and minimally-supervised fashion. We use Nirvana to produce models and rotation curves for 1263 unique barred MaNGA galaxies and a matched unbarred control sample We present our modeling approach, tests of its efficacy, and validation against existing visual bar classifications. Nirvana finds elevated non-circular motions in galaxies identified as bars in imaging, and bar position angles that agree well with visual measurements. The Nirvana-MaNGA barred and control samples provide a new opportunity for studying the influence of non-axisymmetric internal disk kinematics in a large statistical sample.

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arXiv2024

The Completed SDSS-IV extended Baryon Oscillation Spectroscopic Survey: Cosmological Implications from two Decades of Spectroscopic Surveys at the Apache Point observatory

We present the cosmological implications from final measurements of clustering using galaxies, quasars, and Ly$α$ forests from the completed Sloan Digital Sky Survey (SDSS) lineage of experiments in large-scale structure. These experiments, composed of data from SDSS, SDSS-II, BOSS, and eBOSS, offer independent measurements of baryon acoustic oscillation (BAO) measurements of angular-diameter distances and Hubble distances relative to the sound horizon, $r_d$, from eight different samples and six measurements of the growth rate parameter, $fσ_8$, from redshift-space distortions (RSD). This composite sample is the most constraining of its kind and allows us to perform a comprehensive assessment of the cosmological model after two decades of dedicated spectroscopic observation. We show that the BAO data alone are able to rule out dark-energy-free models at more than eight standard deviations in an extension to the flat, $Λ$CDM model that allows for curvature. When combined with Planck Cosmic Microwave Background (CMB) measurements of temperature and polarization the BAO data provide nearly an order of magnitude improvement on curvature constraints. The RSD measurements indicate a growth rate that is consistent with predictions from Planck primary data and with General Relativity. When combining the results of SDSS BAO and RSD with external data, all multiple-parameter extensions remain consistent with a $Λ$CDM model. Regardless of cosmological model, the precision on $Ω_Λ$, $H_0$, and $σ_8$, remains at roughly 1\%, showing changes of less than 0.6\% in the central values between models. The inverse distance ladder measurement under a o$w_0w_a$CDM yields $H_0= 68.20 \pm 0.81 \, \rm km\, s^{-1} Mpc^{-1}$, remaining in tension with several direct determination methods. (abridged)

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arXiv2024

Early Commissioning Results of Slit Mask Integral Field Units on the Southern African Large Telescope

Three fibre feed integral field units (IFUs), called Slit Mask IFUs (SMI), are being developed in the SAAO fibre-lab for the Robert Stobie Spectrograph (RSS). The smaller, 200 micron fibre IFU (SMI-200) has 309 x 0.9 arcsec diameter spatial elements covering an elongated hexagonal footprint of 18 $\times$ 23 arcsec is now being commissioned. The larger, 300 (400) micron fibre IFU, SMI-300 (SMI-400), has 221 $\times$ 1.35 arcsec (178 $\times$ 1.8 arcsec) diameter spatial elements covering an on-sky area of 18 $\times$ 29 sq. arcsec (21 $\times$ 44 sq. arcsec). In all SMI units there are two groups of 13 fibres offset by roughly 50 arcsec on either side of the primary array to sample sky. SMI-200 provides a median spectral resolution of 2400 at H$\upalpha$ wavelengths in a low resolution mode simultaneously covering 370 to 740 nm. At a higher grating angles the SMI-200 delivers spectral resolution up to 10,000. A future red spectrograph arm for RSS will extend the simultaneous wavelength coverage up to 900 nm at a median resolution of 6000 for the same IFU. With this upcoming red arm and with the fibre-fed, near-infrared spectrograph NIRWALS on SALT, SMI-300 enables wavelength coverage from blue to NIR wavelengths at the same spatial resolution and footprint. The SMI units are inserted in the same fashion as the existing long-slit cassettes at the SALT focal plane. Prismatic fold mirrors direct the focal plane into the fibre IFU and then back into the RSS collimator after the fibres are routed 180 deg within the cassette and formatted into a pseudo-slit. Fold-prisms ensure that the spectrograph collimator continues to see the same focal plane. In this paper we report the laboratory characterization and on-sky commissioning-performance of the first Slit Mask IFU, SMI-200.

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arXiv2024

Asymmetric drift in MaNGA: Mass and radially-dependent stratification rates in galaxy disks

We measure the age-velocity relationship from the lag between ionized gas and stellar tangential speeds in ~500 nearby disk galaxies from MaNGA in SDSS-IV. Selected galaxies are kinematically axisymmetric. Velocity lags are asymmetric drift, seen in the Milky Way's (MW) solar neighborhood and other Local Group galaxies; their amplitude correlates with stellar population age. The trend is qualitatively consistent in rate (d(sigma)/dt) with a simple power-law model where sigma is proportional to t^b that explains the dynamical phase-space stratification in the solar neighborhood. The model is generalized based on disk dynamical times to other radii and other galaxies. We find in-plane radial stratification parameters sigma_(0,r} (dispersion of the youngest populations) in the range of 10-40 km/s and 0.2<b_r<0.5 for MaNGA galaxies. Overall b_r increases with galaxy mass, decreases with radius for galaxies above 10.4 dex (M_solar) in stellar mass, but is ~constant with radius at lower mass. The measurement scatter indicates the stratification model is too simple to capture the complexity seen in the data, unsurprising given the many possible astrophysical processes that may lead to stellar population dynamical stratification. Nonetheless, the data show dynamical stratification is broadly present in the galaxy population, with systematic trends in mass and density. The amplitude of the asymmetric drift signal is larger for the MaNGA sample than the MW, and better represented in the mean by what is observed in the disks of M31 and M33. Either typical disks have higher surface-density or, more likely, are dynamically hotter (hence thicker) than the MW.

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arXiv2024

The Sloan Digital Sky Survey Reverberation Mapping Project: Key Results

We present the final data from the Sloan Digital Sky Survey Reverberation Mapping (SDSS-RM) project, a precursor to the SDSS-V Black Hole Mapper Reverberation Mapping program. This data set includes 11-year photometric and 7-year spectroscopic light curves for 849 broad-line quasars over a redshift range of 0.1 =0.62+-0.07 for the line dispersion measured from the RMS spectrum. The intrinsic scatter of individual virial factors is 0.31+-0.07 dex, indicating a factor of two systematic uncertainty in RM black hole masses. Our lag measurements reveal significant R-L relations for Hbeta and MgII at high redshift, consistent with the latest measurements based on heterogeneous samples. While we are unable to robustly constrain the slope of the R-L relation for CIV given the limited dynamical range in luminosity, we found substantially larger scatter in CIV lags at fixed L1350. Using the SDSS-RM lag sample, we derive improved single-epoch (SE) mass recipes for Hbeta, MgII and CIV, which are consistent with their respective RM masses as well as between the SE recipes from two different lines, over the luminosity range probed by our sample. The new Hbeta and MgII recipes are approximately unbiased estimators at given RM masses, but there are systematic biases in the CIV recipe. The intrinsic scatter of SE masses around RM masses is ~0.45 dex for Hbeta and MgII, increasing to ~0.58 dex for CIV.

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arXiv2024

SDSS-IV MaNGA: Calibration of astrophysical line-widths in the Hα region using HexPak observations

We have re-observed $\rm\sim$40 low-inclination, star-forming galaxies from the MaNGA survey ($\upsigma\sim65$~\kms) at $\sim$6.5 times higher spectral resolution ($\upsigma\sim10$~\kms) using the HexPak integral field unit on the WIYN 3.5m telescope. The aim of these observations is to calibrate MaNGA's instrumental resolution and to characterize turbulence in the warm interstellar medium and ionized galactic outflows. Here we report the results for the H$\rm\upalpha$ region observations as they pertain to the calibration of MaNGA's spectral resolution. Remarkably, we find that the previously-reported MaNGA line-spread-function (LSF) Gaussian width is systematically underestimated by only 1\%. The LSF increase modestly reduces the characteristic dispersion of HII regions-dominated spectra sampled at 1-2 kpc spatial scales from 23 to 20 km s$^{-1}$ in our sample, or a 25\% decrease in the random-motion kinetic energy. This commensurately lowers the dispersion zeropoint in the relation between line-width and star-formation rate surface-density in galaxies sampled on the same spatial scale. This modest zero-point shift does not appear to alter the power-law slope in the relation between line-width and star-formation rate surface-density. We also show that adopting a scheme whereby corrected line-widths are computed as the square root of the median of the difference in the squared measured line width and the squared LSF Gaussian avoids biases and allows for lower SNR data to be used reliably.

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arXiv2023

The Baryonic Content of Galaxies Mapped by MaNGA and the Gas Around Them

We analyze the cool gas in and around 14 nearby galaxies (at $z$$<$0.1) mapped with the SDSS-IV MaNGA survey by measuring absorption lines produced by gas in spectra of background quasars/AGN at impact parameters of 0-25 effective radii from the galaxy center. Using HST/COS, we detect absorption at the galaxy redshift and measure or constrain column densities of neutral (H I, N I, O I, Ar I), low-ionization (Si II, S II, C II, N II Fe II), and high-ionization (Si III, Fe III, N V, O VI) species for 11 galaxies. We derive the ionization parameter and ionization-corrected metallicity using CLOUDY photo-ionization models. The H I column density ranges from $\sim$$10^{13}$ to $\sim$$10^{20}\,{\rm cm^{-2}}$ and decreases with impact parameter for $r \ge R_{e}$. Galaxies with higher stellar mass have weaker H I absorption. Comparing absorption velocities with MaNGA radial velocity maps of ionized gas line emissions in galactic disks, we find that the neutral gas seen in absorption co-rotates with the disk out to $\sim$10 $R_{e}$. Sight lines with lower elevation angles show lower metallicities, consistent with the metallicity gradient in the disk derived from MaNGA maps. Higher elevation angle sight lines show higher ionization, lower H I-column density, super-solar metallicity, and velocities consistent with the direction of galactic outflow. Our data offer the first detailed comparisons of CGM properties (kinematics and metallicity) with extrapolations of detailed galaxy maps from integral field spectroscopy; similar studies for larger samples are needed to more fully understand how galaxies interact with their CGM.

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arXiv2023

The need for multicomponent dust attenuation in modeling nebular emission: Constraints from SDSS-IV MaNGA

A fundamental assumption adopted in nearly every extragalactic emission-line study is that the attenuation of different emission lines can be described by a single attenuation curve. Here we show this assumption fails in many cases with important implications for derived results. We developed a new method to measure the differential nebular attenuation among three kinds of transitions: the Balmer lines of hydrogen, high-ionization transitions, and low-ionization transitions. This method bins the observed data in a multidimensional space spanned by attenuation-insensitive line ratios. Within each small bin, the variations in line ratios are mainly driven by the variations in the nebular attenuation. This allows us to measure the nebular attenuation using both forbidden lines and Balmer lines. We applied this method to a sample of 2.4 million star-forming spaxels from SDSS-IV MaNGA. We found that the attenuation of high ionization lines and Balmer lines can be well described by a single Fitzpatrick (1999) extinction curve with $R_V=3.1$. However, no single attenuation curve can simultaneously account for all three transitions. This strongly suggests that different lines have different effective attenuations, likely because spectroscopy at kiloparsec resolutions mixes multiple regions with different intrinsic line ratios and different levels of attenuation. As a result, the assumption that different lines follow the same attenuation curve breaks down. Using a single attenuation curve determined by Balmer lines to correct attenuation-sensitive forbidden line ratios could bias the nebular parameters derived by 0.06--0.25 dex at $A_V = 1$, depending on the details of the dust attenuation model. Observations of a statistically large sample of H II regions with high spatial resolutions and large spectral coverage are vital for improved modeling and deriving accurate corrections for this effect.

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arXiv2022

Slit Mask Integral Field Units for the Southern African Large Telescope

Two fibre integral field units (IFU) are being built in the SAAO fibre-lab for the Robert Stobie Spectrograph's visible arm and the future red arm. Each IFU sits in its own slit-mask cassette and is referred to as a slit-mask IFU (SMI). They will be available some time in 2022. The smaller, 200 micron fibre IFU has 309 X 0.9 arcsec diameter spatial elements covering an elongated hexagonal footprint of 18 X 23 arcsec. The larger, 400 micron fibre IFU has 178 X 1.8 arcsec diameter spatial elements covering an on-sky area of 21 X 44 arcsec. In both cases there are two groups of 13 fibres offset by roughly 50 arcsec on either side of the primary array to sample sky. The 1.8 and 0.9 arcsec spatial resolution SMIs provide median spectral resolution of 1200 and 2400 respectively at H alpha wavelengths in the low resolution mode covering 320 to 740 nm bandpass. At a higher grating angle the SMI will deliver spectral resolution up to 5000 and 10000 with 400 and 200 micron core fibre respectively. A future red-arm will extend the simultaneous wavelength coverage up to 900 nm at a median resolution of 3000/6000 for the same flavors of IFUs. SMIs are inserted in the same fashion as the existing longslit cassettes at the SALT focal plane. Prismatic fold mirrors direct the focal plane into the fibre IFU and then back into the RSS collimator after the fibres are routed 180 deg within the cassette and formatted into a pseudo-slit. Fold prisms ensure that the spectrograph collimator continues to see the same focal plane. In this paper we describe the design, fabrication, assembly and characterization of Slit Mask IFUs.

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arXiv2022

The MaNGA FIREFLY Value-Added-Catalogue: resolved stellar populations of 10,010 nearby galaxies

We present the MaNGA FIREFLY Value-Added-Catalogue (VAC) - a catalogue of ~3.7 million spatially resolved stellar population properties across 10,010 nearby galaxies from the final data release of the MaNGA survey. The full spectral fitting code firefly is employed to derive parameters such as stellar ages, metallicities, stellar and remnant masses, star formation histories, star formation rates and dust attenuation. In addition to Voronoi-binned measurements, our VAC also provides global properties, such as central values and radial gradients. Two variants of the VAC are available: presenting the results from fits using the M11-MILES and the novel MaStar stellar population models. MaStar allows to constrain the fit over the whole MaNGA wavelength range, extends the age-metallicity parameter space, and uses empirical spectra from the same instrument as MaNGA. The fits employing MaStar models find on average slightly younger ages, higher mass-weighted metallicities and smaller colour excesses. These differences are reduced when matching wavelength range and converging template grids. We further report that FIREFLY stellar masses are systematically lower by ~0.3 dex than masses from the MaNGA PCA and Pipe3D VACs, but match masses from the NSA best with only ~0.1 dex difference. Finally, we show that FIREFLY stellar ages correlate with spectral index age indicators H$δ_A$ and $D_n$(4000), though with a clear additional metallicity dependence.

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arXiv2022

Optimum telescope focal ratios for microlens-to-fiber coupled integral field spectrographs

We describe the optimum telescope focal ratio for a two-element, three surface, telecentric image-transfer microlens-to-fiber coupled integral field unit within the constraints imposed by micro-optics fabrication and optical aberrations. We create a generalized analytical description of the micro-optics optical parameters from first principals. We find that the optical performance, including all aberrations, of a design constrained by an analytic model considering only spherical aberration and diffraction matches within +/-4% of a design optimized by ray-tracing software such as Zemax. The analytical model does not require any compromise on the available clear aperture; about 90% mechanical aperture of a hexagonal microlens is available for light collection. The optimum telescope f-ratio for a 200μm core fiber fed at f/3.5 is between f/7 and f/12. We find the optimum telescope focal ratio changes as a function of fiber core diameter and fiber input beam speed. A telescope focal ratio of f/8 would support the largest range of fiber diameters (100 to 500μm) and fiber injection speeds (between f/3 and f/5). The optimization of telescope and lenslet-coupled fibers is relevant for the design of high-efficiency dedicated survey telescopes, and for retro-fitting existing facilities via introducing focal macro-optics to match the instrument input requirements.

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arXiv2022

PetroFit: A Python Package for Computing Petrosian Radii and Fitting Galaxy Light Profiles

PetroFit is an open-source Python package, based on Astropy and Photutils, that can calculate Petrosian profiles and fit galaxy images. It offers end-to-end tools for making accurate photometric measurements, estimating morphological properties, and fitting 2D models to galaxy images. Petrosian metric radii can be used for model parameter estimation and aperture photometry to provide accurate total fluxes. Correction tools are provided for improving Petrosian radii estimates affected by galaxy morphology. PetroFit also provides tools for sampling Astropy-based models (including custom profiles and multi-component models) onto image grids and enables PSF convolution to account for the effects of seeing. These capabilities provide a robust means of modeling and fitting galaxy light profiles. We have made the PetroFit package publicly available on GitHub (PetroFit/petrofit) and PyPi (pip install petrofit).

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arXiv2022

SDSS-IV MaNGA: Exploring the local scaling relations for N/O

We present, for the first time, the relationship between local stellar mass surface density, $\mathrm{Σ_{*}}$, and N/O derived from SDSS-IV MaNGA data, using a sample of $792765$ high signal-to-noise ratio star-forming spaxels. Using a combination of phenomenological modelling and partial correlation analysis, we find that $\mathrm{Σ_{*}}$ alone is insufficient to predict the N/O in MaNGA spaxels, and that there is an additional dependence on the local star formation rate surface density, $\mathrm{Σ_{SFR}}$. This effect is a factor of $3$ stronger than the dependence of 12+log(O/H) on $\mathrm{Σ_{SFR}}$. Surprisingly, we find that the local N/O scaling relations also depend on the total galaxy stellar mass at fixed $Σ_{*}$ as well as the galaxy size at fixed stellar mass. We find that more compact galaxies are more nitrogen rich, even when $\mathrm{Σ_{*}}$ and $\mathrm{Σ_{SFR}}$ are controlled for. We show that $\sim50\%$ of the variance of N/O is explained by the total stellar mass and size. Thus, the evolution of nitrogen in galaxies is set by more than just local effects and does not simply track the build up of oxygen in galaxies. The precise form of the N/O-O/H relation is therefore sensitive to the sample of galaxies from which it is derived. This result casts doubt on the universal applicability of nitrogen-based strong-line metallicity indicators derived in the local universe.

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arXiv2022

SDSS-IV MaNGA: Understanding Ionized Gas Turbulence using Integral Field Spectroscopy of 4500 Star-Forming Disk Galaxies

The Sloan Digital Sky Survey MaNGA program has now obtained integral field spectroscopy for over 10,000 galaxies in the nearby universe. We use the final MaNGA data release DR17 to study the correlation between ionized gas velocity dispersion and galactic star formation rate, finding a tight correlation in which sigma_Ha from galactic HII regions increases significantly from ~ 18-30 km/s broadly in keeping with previous studies. In contrast, sigma_Ha from diffuse ionized gas (DIG) increases more rapidly from 20-60 km/s. Using the statistical power of MaNGA, we investigate these correlations in greater detail using multiple emission lines and determine that the observed correlation of sigma_Ha with local star formation rate surface density is driven primarily by the global relation of increasing velocity dispersion at higher total SFR, as are apparent correlations with stellar mass. Assuming HII region models consistent with our finding that sigma_[O III] < sigma_Ha < sigma_[O I], we estimate the velocity dispersion of the molecular gas in which individual HII regions are embedded, finding values sigma_Mol = 5-30 km/s consistent with ALMA observations in a similar mass range. Finally, we use variations in the relation with inclination and disk azimuthal angle to constrain the velocity dispersion ellipsoid of the ionized gas sigma_z/sigma_r = 0.84 +- 0.03 and sigma_phi/sigma_r = 0.91 +- 0.03, similar to that of young stars in the Galactic disk. Our results are most consistent with theoretical models in which turbulence in modern galactic disks is driven primarily by star formation feedback.

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arXiv2022

The Seventeenth Data Release of the Sloan Digital Sky Surveys: Complete Release of MaNGA, MaStar and APOGEE-2 Data

This paper documents the seventeenth data release (DR17) from the Sloan Digital Sky Surveys; the fifth and final release from the fourth phase (SDSS-IV). DR17 contains the complete release of the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey, which reached its goal of surveying over 10,000 nearby galaxies. The complete release of the MaNGA Stellar Library (MaStar) accompanies this data, providing observations of almost 30,000 stars through the MaNGA instrument during bright time. DR17 also contains the complete release of the Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE-2) survey which publicly releases infra-red spectra of over 650,000 stars. The main sample from the Extended Baryon Oscillation Spectroscopic Survey (eBOSS), as well as the sub-survey Time Domain Spectroscopic Survey (TDSS) data were fully released in DR16. New single-fiber optical spectroscopy released in DR17 is from the SPectroscipic IDentification of ERosita Survey (SPIDERS) sub-survey and the eBOSS-RM program. Along with the primary data sets, DR17 includes 25 new or updated Value Added Catalogs (VACs). This paper concludes the release of SDSS-IV survey data. SDSS continues into its fifth phase with observations already underway for the Milky Way Mapper (MWM), Local Volume Mapper (LVM) and Black Hole Mapper (BHM) surveys.

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