arXiv subjects

Simon Morris

Publications and source records attributed to Simon Morris.

13 recordsLinked to original sources

arXiv2025

Transformational astrophysics and exoplanet science with Habitable Worlds Observatory's High Resolution Imager

Habitable Worlds Observatory (HWO) will be NASA's flagship space telescope of the 2040s, designed to search for life on other planets and to transform broad areas of astrophysics. NASA are seeking international partners, and the UK is well-placed to lead the design and construction of its imaging camera - which is likely to produce the mission's most visible public impact. Early participation in the mission would return investment to UK industry, and bring generational leadership for the UK in space science, space technology, and astrophysics.

astro-ph.IM↗

arXiv2024

The Blue Multi Unit Spectroscopic Explorer (BlueMUSE) on the VLT: science drivers and overview of instrument design

BlueMUSE is a blue-optimised, medium spectral resolution, panoramic integral field spectrograph under development for the Very Large Telescope (VLT). With an optimised transmission down to 350 nm, spectral resolution of R$\sim$3500 on average across the wavelength range, and a large FoV (1 arcmin$^2$), BlueMUSE will open up a new range of galactic and extragalactic science cases facilitated by its specific capabilities. The BlueMUSE consortium includes 9 institutes located in 7 countries and is led by the Centre de Recherche Astrophysique de Lyon (CRAL). The BlueMUSE project development is currently in Phase A, with an expected first light at the VLT in 2031. We introduce here the Top Level Requirements (TLRs) derived from the main science cases, and then present an overview of the BlueMUSE system and its subsystems fulfilling these TLRs. We specifically emphasize the tradeoffs that are made and the key distinctions compared to the MUSE instrument, upon which the system architecture is built.

astro-ph.IM↗

arXiv2021

The relationship between gas and galaxies at z<1 using the Q0107 quasar triplet

We study the distribution and dynamics of the circum- and intergalactic medium using a dense galaxy survey covering the field around the Q0107 system, a unique z~1 projected quasar triplet. With full Ly$\alpha$ coverage along all three lines-of-sight from z=0.18 to z=0.73, more than 1200 galaxy spectra, and two MUSE fields, we examine the structure of the gas around galaxies on 100-1000 kpc scales. We search for H I absorption systems occurring at the same redshift (within 500 $\textrm{km}$ $\textrm{s}^{-1}$) in multiple sightlines, finding with $>$ 99.9% significance that these systems are more frequent in the observed quasar spectra than in a randomly distributed population of absorbers. This is driven primarily by absorption with column densities N(H I) $> 10^{14}$ $\textrm{cm}^{-2}$, whilst multi-sightline absorbers with lower column densities are consistent with a random distribution. Star-forming galaxies are more likely to be associated with multi-sightline absorption than quiescent galaxies. HST imaging provides inclinations and position angles for a subset of these galaxies. We observe a bimodality in the position angle of detected galaxy-absorber pairs, again driven mostly by high-column-density absorbers, with absorption preferentially along the major and minor axes of galaxies out to impact parameters of several hundred kpc. We find some evidence supporting a disk/outflow dichotomy, as H I absorbers near the projected major-axis of a galaxy show line-of-sight velocities that tend to align with the rotation of that galaxy, whilst minor-axis absorbers are twice as likely to exhibit O VI at the same redshift.

astro-ph.GA↗

arXiv2020

MOSAIC: the high-multiplex and multi-IFU spectrograph for the ELT

MOSAIC is the planned multi-object spectrograph for the 39m Extremely Large Telescope (ELT). Conceived as a multi-purpose instrument, it offers both high multiplex and multi-IFU capabilities at a range of intermediate to high spectral resolving powers in the visible and the near-infrared. MOSAIC will enable unique spectroscopic surveys of the faintest sources, from the oldest stars in the Galaxy and beyond to the first populations of galaxies that completed the reionisation of the Universe--while simultaneously opening up a wide discovery space. In this contribution we present the status of the instrument ahead of Phase B, showcasing the key science cases as well as introducing the updated set of top level requirements and the adopted architecture. The high readiness level will allow MOSAIC to soon enter the construction phase, with the goal to provide the ELT community with a world-class MOS capability as soon as possible after the telescope first light.

astro-ph.IM↗

arXiv2018

The ELT-MOS (MOSAIC): towards the construction phase

When combined with the huge collecting area of the ELT, MOSAIC will be the most effective and flexible Multi-Object Spectrograph (MOS) facility in the world, having both a high multiplex and a multi-Integral Field Unit (Multi-IFU) capability. It will be the fastest way to spectroscopically follow-up the faintest sources, probing the reionisation epoch, as well as evaluating the evolution of the dwarf mass function over most of the age of the Universe. MOSAIC will be world-leading in generating an inventory of both the dark matter (from realistic rotation curves with MOAO fed NIR IFUs) and the cool to warm-hot gas phases in z=3.5 galactic haloes (with visible wavelenth IFUs). Galactic archaeology and the first massive black holes are additional targets for which MOSAIC will also be revolutionary. MOAO and accurate sky subtraction with fibres have now been demonstrated on sky, removing all low Technical Readiness Level (TRL) items from the instrument. A prompt implementation of MOSAIC is feasible, and indeed could increase the robustness and reduce risk on the ELT, since it does not require diffraction limited adaptive optics performance. Science programmes and survey strategies are currently being investigated by the Consortium, which is also hoping to welcome a few new partners in the next two years.

astro-ph.IM↗

arXiv2015

The Science Case for Multi-Object Spectroscopy on the European ELT

This White Paper presents the scientific motivations for a multi-object spectrograph (MOS) on the European Extremely Large Telescope (E-ELT). The MOS case draws on all fields of contemporary astronomy, from extra-solar planets, to the study of the halo of the Milky Way and its satellites, and from resolved stellar populations in nearby galaxies out to observations of the earliest 'first-light' structures in the partially-reionised Universe. The material presented here results from thorough discussions within the community over the past four years, building on the past competitive studies to agree a common strategy toward realising a MOS capability on the E-ELT. The cases have been distilled to a set of common requirements which will be used to define the MOSAIC instrument, entailing two observational modes ('high multiplex' and 'high definition'). When combined with the unprecedented sensitivity of the E-ELT, MOSAIC will be the world's leading MOS facility. In analysing the requirements we also identify a high-multiplex MOS for the longer-term plans for the E-ELT, with an even greater multiplex (>1000 targets) to enable studies of large-scale structures in the high-redshift Universe. Following the green light for the construction of the E-ELT the MOS community, structured through the MOSAIC consortium, is eager to realise a MOS on the E-ELT as soon as possible. We argue that several of the most compelling cases for ELT science, in highly competitive areas of modern astronomy, demand such a capability. For example, MOS observations in the early stages of E-ELT operations will be essential for follow-up of sources identified by the James Webb Space Telescope (JWST). In particular, multi-object adaptive optics and accurate sky subtraction with fibres have both recently been demonstrated on sky, making fast-track development of MOSAIC feasible.

astro-ph.GA↗

arXiv2013

ELT-MOS White Paper: Science Overview & Requirements

The workhorse instruments of the 8-10m class observatories have become their multi-object spectrographs (MOS), providing comprehensive follow-up to both ground-based and space-borne imaging. With the advent of deeper imaging surveys from, e.g., the HST and VISTA, there are a plethora of spectroscopic targets which are already beyond the sensitivity limits of current facilities. This wealth of targets will grow even more rapidly in the coming years, e.g., after the completion of ALMA, the launch of the JWST and Euclid, and the advent of the LSST. Thus, one of the key requirements underlying plans for the next generation of ground-based telescopes, the Extremely Large Telescopes (ELTs), is for even greater sensitivity for optical and infrared spectroscopy. Here we revisit the scientific motivation for a MOS capability on the European ELT, combining updated elements of science cases advanced from the Phase A instrument studies with new science cases which draw on the latest results and discoveries. These science cases address key questions related to galaxy evolution over cosmic time, from studies of resolved stellar populations in nearby galaxies out to observations of the most distant galaxies, and are used to identify the top-level requirements on an 'E-ELT/MOS'. We argue that several of the most compelling ELT science cases demand MOS observations, in highly competitive areas of modern astronomy. Recent technical studies have demonstrated that important issues related to e.g. sky subtraction and multi-object AO can be solved, making fast- track development of a MOS instrument feasible. To ensure that ESO retains world leadership in exploring the most distant objects in the Universe, galaxy evolution and stellar populations, we are convinced that a MOS should have high priority in the instrumentation plan for the E-ELT.

astro-ph.CO↗

arXiv2009

EAGLE Spectroscopy of Resolved Stellar Populations Beyond the Local Group

We give an overview of the science case for spectroscopy of resolved stellar populations beyond the Local Group with the European Extremely Large Telescope (E-ELT). In particular, we present science simulations undertaken as part of the EAGLE Phase A design study for a multi--integral-field-unit, near-infrared spectrograph. EAGLE will exploit the unprecedented primary aperture of the E-ELT to deliver AO-corrected spectroscopy across a large (38.5 sq. arcmin) field, truly revolutionising our view of stellar populations in the Local Volume.

astro-ph.IM↗

arXiv2009

EAGLE Spectroscopy of Resolved Stellar Populations Beyond the Local Group

Valuable insights into galaxy evolution can be gleaned from studies of resolved stellar populations in the local Universe. Deep photometric surveys have provided tracers of the star-formation histories in galaxies from 0.8-16 Mpc, but without robust chemical abundances and stellar kinematics from spectroscopy, their sub-structures and assembly histories remain hidden from us. In this context, we introduce the EAGLE design study for a multi--integral-field-unit, near-infrared spectrograph for the European Extremely Large Telescope (E-ELT). EAGLE will exploit the unprecedented light-gathering power of the E-ELT to deliver AO-corrected spectroscopy across a large (38.5 sq. arcmin) field, truly revolutionising our view of stellar populations in the Local Volume.

astro-ph.IM↗

arXiv2007

A Population of Faint Extended Line Emitters and the Host Galaxies of Optically Thick QSO Absorption Systems

We have conducted a long slit search for low surface brightness Lyman-alpha emitters at redshift 2.67 < z < 3.75. A 92 hour long exposure with VLT/FORS2 down to a 1-sigma surface brightness detection limit of 8x10^-20 erg/cm2/s/sqarcsec yielded a sample of 27 single line emitters with fluxes of a few times 10^-18 erg/s/cm2. We present arguments that most objects are indeed Lyman-alpha. The large comoving number density, the large covering factor, dN/dz ~ 0.2-1, and the often extended Lyman-alpha emission suggest that the emitters be identified with the elusive host population of damped Lyman-alpha systems (DLAS) and high column density Lyman limit systems. A small inferred star formation rate, perhaps supplanted by cooling radiation, appears to energetically dominate the Lyman-alpha emission, and is consistent with the low metallicity, low dust content, and theoretically inferred low masses of DLAS, and with the relative lack of success of earlier searches for their optical counterparts. (abridged)

astro-ph↗

arXiv2006

A multi-object, multi-field spectrometer and imager for a European ELT

One of the highlights of the European ELT Science Case book is the study of resolved stellar populations, potentially out to the Virgo Cluster of galaxies. A European ELT would enable such studies in a wide range of unexplored distant environments, in terms of both galaxy morphology and metallicity. As part of a small study, a revised science case has been used to shape the conceptual design of a multi-object, multi-field spectrometer and imager (MOMSI). Here we present an overview of some key science drivers, and how to achieve these with elements such as multiplex, AO-correction, pick-off technology and spectral resolution.

astro-ph↗

arXiv2002

The origin of [Fe II] emission in NGC 4151

The centre of NGC 4151 has been observed in the J-band with the SMIRFS integral field unit (IFU) on the UK Infrared Telescope. A map of [Fe II] emission is derived, and compared with the distributions of the optical narrow line region and radio jet. We conclude that, because the [Fe II] emission is associated more closely with the visible narrow-line region than with the radio jet, it arises mainly through photoionization of gas by collimated X-rays from the Seyfert nucleus. The velocity field and strength with respect to [Pa B] are found to be consistent with this argument. The performance of the IFU is considered briefly, and techniques for observation and data analysis are discussed.

astro-ph↗

arXiv2001

A Million Element Integral Field Unit (MEIFU)

We describe an instrument concept that will provide simultaneous spectra for a million spatial samples on the sky. With the proposed field of view and spectral resolution, it will be able to measure redshifts and line strengths for around 2-4000 z~3-7 galaxies in a 16 night campaign. The main science driver is to obtain a complete census of the star formation properties of galaxies with 2.5<z<6.7 as a function of luminosity, environment, morphology and redshift. This survey will also allow us to study the evolution of the 3 dimensional power spectrum and test the connection between these early galaxies and the large scale structure of the Lyman Alpha forest. Additional science drivers include [OII] emitters with 0.13<z<1.52, abundance gradients in nearby galaxies, searches for planetary nebulae in nearby galaxy groups and clusters, lensed emission line objects, and spectroscopic searches for objects with continuum breaks. We expect that this instrument will make an ideal partner to the HST ACS, where ACS morphology and broadband colour information can complement the MEIFU spectroscopy and help remove any degeneracies in line identification.

astro-ph↗