HAWK-I Science Verification - Proposal Abstracts


Doherty et al.: Proto-clusters in the environs of redshift z~2 Radio Galaxies

Programme ID: 60.A-9284(A)
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There is now strong evidence that galaxy evolution is closely linked to environment and that the oldest, reddest galaxies locally are found in large clusters. Hence to study the early stages of galaxy evolution we need to study the highest redshift (proto-)clusters. However, the number of currently known high-z clusters is small. We propose to improve the situation using HAWK-I to search for proto-cluster candidates, by looking for over-densities in the environs of high redshift radio galaxies at z > 2. Several such proto-clusters have been found using narrowband imaging to locate overdensities of Lyman-alpha emitters. Recently, new near-IR imaging from MOIRCS-Subaru also indicates an excess of red galaxies clustered towards similar radio galaxies. We propose to use three of the HAWK-I narrow-band filters to search for emission-line galaxies at the appropriate redshifts and at the same time search for older, redder, evolved galaxies using J-K colours from broadband imaging.


Fontana et al.: A deep infrared view on galaxies in the early Universe

Programme ID: 60.A-9284(B)
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We propose to test the Hawk�I capabilities in exploring the early phases of galaxy evolution through wide area multicolor surveys. The main scientific goal of such observations is to obtain the first self-consistent sample of "Lyman Break Galaxies" at z~7, selected by means of an uktradeep Y-band image, providing a new view on the epoch at the end of the re-ionization. We propose to carry on these observation on a single pointing in the GOODS-South field to exploit the unique set of public ultradeep ancillary data already available, most notably the ultradeep image in the z band from HST that is necessary to identify drop�outs. We also propose to use the K, J and H braod�band filters available in Hawk�I to match the depth of the HST and Spitzer data in GOODS, on order to explore for the first time the statistics and diversification of spectral types on a mass complete sample of M>5x10^10 Msol galaxies up to z=3.5, using a set of well characterized color selection criteria.

Proposal combined with: Venemans et al. - HAWK-I confirmation of the first z > 7.5 galaxy

We propose to use HAWK-I observations in the NB1060 and Y filters of the GOODS South field (03:32:32.0, -25:45:00) to confirm a candidate z = 7.7 Lyman alpha emitter previously discovered on the VLT with DAZLE (Dark Ages Z Lyman alpha Explorer). These observations will be a vital demonstration of the scientific potential of HAWK-I in directly probing the Epoch of Reionisation. As well as confirming or disproving the nature of the DAZLE candidate, these SV observations alone will form a sufficient complete dataset to put a constraint on the number of luminous star forming galaxies at z = 7.7, when combined with the existing public GOODS data which uniquely includes HST/ACS data in B, V, i and z over the whole HAWK-I field (unlike any other field visible from Paranal).


Franx et al.: The missing link: a deep K-band map of the Extended-CDFS

Programme ID: 60.A-9284(C)
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Massive galaxies form the bulk of their stars and black hole mass early in the history of the universe, with star formation and AGN activity shifting to lower masses at later times. Theory suggests that the two processes are coupled: accretion onto black holes provides the energy to halt star formation once a certain mass scale is reached. Testing the �downsizing� scenario and the link to AGN activity is a premier goal in contemporary cosmology. However, a limiting observational factor is the lack of deep, wide-area imaging in the near-IR. The near-IR plays a crucial role in 1) interpreting the multiwavelength emission of galaxies at z>1, in particular in estimating the stellar masses from their SEDs, and 2) providing targets for follow-up near-IR spectroscopy. Here, we propose to observe the 0.5deg x 0.5deg Extended-CDFS in the K-band with HAWK-I. The E-CDFS has the best Spitzer, Chandra, and HST/ACS coverage of any field of comparable size, and equally importantly: all data are publicly available. The addition of deep K-band imaging will immediately help constrain AGN activity, star formation, and sizes of ~1000 massive galaxies at z=1-3 and will identify massive red galaxies at z>4 if they exist. HAWK-I is the only instrument that delivers the necessary combination of image quality, area, and depth. A strong legacy aspect of this proposal is that the E-CDFS has the perfect declination for vigorous follow-up with VLT and ALMA of ob jects found and characterized in the HAWK-I data.


Gieles et al.: Fundamental properties of star clusters in nearby spiral galaxies

Programme ID: 60.A-9284(D)
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We propose near infrared (NIR) imaging of galaxies with moderate star formation rate (NGC 1313, NGC 2997, NGC 4548, NGC 7793) to high star formation rate (M83) using HAWK-I to complement existing wide field optical data-sets and study their star cluster populations. The NIR has the ad- vantages that cluster colours are less affected by extinction enabling us to disentangle the degeneracy between extinction and age and provide a well defined and unbiased sample that can not be obtained from optical data alone. The combination of NIR with optical data, however, and the large field of view of HAWK-I allow us to construct the cluster luminosity function, the cluster initial mass func- tion and the cluster age distribution of entire cluster populations in different environments. This will shed light into how cluster masses depend on the star formation rate of the host galaxy and how the early disruption due to the removal of natal gas, or infant mortality of clusters, depends on local variables. The azimuthal distance to the spiral arms, that is, the place where clusters form, combined with cluster ages will provide us kinematical information of the density wave in the host galaxy. We suggest 2 priorities, with 3 nearby galaxies that have been studies using HST/ACS data recently as priority A (NGC 1313, M83, NGC 7793) and 2 slightly more distant galaxies as priority B (NGC 2997 and NGC 4548). If time does not allow execution of all, we can still meet our science goals with the priority A targets.


Kneib et al.: A Deep Infrared Survey through a Massive Cluster Lens

Programme ID: 60.A-9284(E)
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We propose here to conduct a deep infrared survey of distant galaxies through a massive cluster lens. Combining the Hawk-I sensitivity and wide field of view with the cluster magnification ranging from 0.3 to 3 magnitude, this survey will provide unique information regarding: i) the number density of distant "Lyman-break" galaxies at redshift larger than z=7, which are key numbers to constrain the epoch of reionization; ii) the shape of the galaxy luminosity and stellar mass function at low luminosity as a function of redshift (mainly for 1 z 4), which is key for the understanding of galaxy evolution models; iii) the cluster luminosity function, thus giving a proper estimate of the cluster stellar mass which will be compared to the total mass derived by the strong and weak lensing modeling, thus providing important information on cluster growth.

Proposal combined with: Unveiling the universe at z > 7 with HAWK-I

The most distant ob ject detected in the universe lies at a redshift z=7. This epoch is marked by some of the most important events in the history of the universe: global re-ionisation and the formation of the first stars and galaxies. However, our ability to study the universe at z>7 has - until the advent of HAWK-I - been limited by the lack of large field near infra-red (NIR) cameras on 8m class telescopes. Narrow-band (NB) imaging observations are a highly effective technique for detecting Ly-alpha emitting galaxies out to the highest redshifts. We propose to use HAWK-I to observe a single field directed toward a massive galaxy cluster. The resulting NB image will provide a sensitive test for the presence of gravitationally lensed z>7 galaxies. Many interloping z 7 galaxies will be detected in this image (and recognised as such by our techniques) and will be of wider interest for numerous follow-up studies. The NB observations will provide a critical test of the performance of HAWK-I at the faintest signal levels. In addition, the low background present in the NB1060 filter will test the performance of HAWK-I when imaging at sky noise levels close to the read noise.


Kuntschner et al.: The globular cluster system of NGC 3115

Programme ID: 60.A-9284(F)
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Globular Clusters (GCs) provide important tools to distinguish between competing models for the formation of their host galaxies. The combination of optical and IR photometry is a very powerful tool to investigate the age distribution of globular clusters in a given system. Currently available samples are severely limited by the spatial coverage of the IR data. In this proposal we wish to investigate the GC system of the nearest S0 galaxy NGC 3115 using Hawk-I to obtain wide field, deep J,H,K-band imaging. With the unprecedented FoV and sensitivity of Hawk-I we will increase the survey area as compared to the existing IR imaging by a factor of ~13 with only one central pointing. The number of observed GC suitable for an optical-IR color analysis will be increased by at least a factor of 4. Ample ground based optical imaging, matching the FoV of HAWK-I, is available for NGC 3115 and already in our hands (e.g., VLT-FORS2, Gemini GMOS).


Larsen et al.: Star Cluster Populations in the Merger Remnant NGC 1316

Programme ID: 60.A-9284(G)
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We propose to image the intermediate-age (~3 Gyr) merger remnant NGC 1316 and study its popula- tion of massive (globular) star clusters. Previous studies have shown that NGC 1316 hosts a significant population of clusters of which some have ages corresponding to the merger event. However, it remains poorly constrained exactly what fraction of the clusters were formed in the merger. Deep, wide-field HAWK-I imaging combined with existing optical data will allow us to clearly separate the various cluster populations in NGC 1316, constrain their ages and metallicities, and compare their spatial distributions. Such data will complement our recent VIMOS spectroscopy, which will provide ages for a brighter subset of the clusters and radial velocities to a limiting magnitude comparable to that of our proposed HAWK-I imaging. The VIMOS data will also provide the optical imaging required to supplement the HAWK-I near-IR data. In addition to yielding important insight into the properties of intermediate-age and old star cluster populations in NGC 1316, the simultaneous availability of optical/near-IR imaging and spectroscopic data for a large sample of star clusters spanning a range of ages will also provide an important database for testing the consistency of both techniques.


Lidman et al.: The build-up of the red sequence in rich galaxy clusters

Programme ID: 60.A-9284(H)
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We propose to examine the build-up of the red sequence in rich galaxy clusters by observing the region surrounding one of the most distant massive clusters known, XMMU J2235.3-2557 at z = 1.39. Specifically, we want see if the red sequence is truncated at faint magnitudes, which would be evidence that the most massive galaxies on the red sequence form first.


McCaughrean et al.: Proper motions in HH 212: tying down the reference frame and extending the baseline

Programme ID: 60.A-9284(I)
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We propose taking a deep, high spatial resolution H2 2.122 microns image of the highly symmetric protostellar jet HH 212 with HAWK-I. We conducted a long-term (2000�2006) proper motion study of HH 212 with ISAAC, measuring transverse motions in the outflow down to 20 km s-1 , in order to trace the dynamical history of the jet and thus the accretion history of the underlying protostar. However, the limited field-of-view of ISAAC meant that, in order to cover the whole jet (~215 arcsec), a two-position mosaic was required. Combined with the slight, but time-variable (over years) optical distortion in ISAAC, we have encountered significant difficulties in the data analysis of jet motions at the sub-pixel level. By contrast, HAWK-I has a large enough field that HH 212 can be covered in its entirety in one quadrant alone: we are thus proposing to obtain new HAWK-I data to provide an astrometrically-stable, deep, high-resolution template image against which to fit our extant ISAAC imagery. Not insignificantly, these observations would extend our proper-motion monitoring baseline from 5 to 7 years, improving the velocity resolution even further, as well as providing a direct test of the narrow-band sensitivity of HAWK-I.


Mora et al.: Star formation in the Small Magellanic Cloud NGC 602 region

Programme ID: 60.A-9284(J)
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Star formation is currently taking place in the open cluster NGC 602 in the Small Magellanic Cloud (SMC). A population of low-intermediate mass, pre-main sequence (PMS) stars (M = 0.6-3.0Msol, >4 Myr) has been detected with HST/ACS deep V and I images, while Class 0-II Young Stellar Ob jects (YSOs) have been detected with Spitzer/IRAC images and are apparently related to optically detected PMS stars. Since such association is surprising, we propose to make use of the high sensitivity and resolution of VLT/HAWK-I to obtain deep, near infrared J , H and Ks images of NGC 602 in order to: a) clarify and study the true nature of the YSOs and their optical counterparts, by tracing the essential Near InfraRed (NIR) part of the SEDs, b) detect and characterize the NGC 602 PMS population down to late M spectral types (M>0.15M). c) eventually discover new faint YSOs in NGC 602 not detected by Spitzer. The large size (~3.5') and distance (m-M = 18.91) of NGC 602 requires an 8m-class telescope with a wide field camera. Therefore, VLT/HAWK-I is the ideal instrument for this study.


Preibisch et al.: The Carina Nebula as a laboratory of massive star feedback

Programme ID: 60.A-9284(K)
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The Great Nebula in Carina is the best galactic analogue of giant extragalactic H II and starburst regions, and is a superb location in which to study the physics of violent massive star formation and the resulting feedback effects, including cloud dispersal and triggered star formation. We propose to use HAWK-I to conduct a deep near-IR survey covering ~0.35 square degrees of the region encompassing several very dense clusters, deeply- embedded protostars, and a more widely dispersed young stellar population. The survey will reveal all young stars in the region through extinction of up to AV~25 mag and brown dwarfs to 35 MJup through 10 mag. The opportunity to obtain these data in HAWK-I SV is extremely timely: in addition to existing large HST optical and Spitzer thermal-IR datasets, we have recently been allocated 1.2 Msec of Chandra time to conduct a spa- tially complete, deep X-ray survey. Together, these X-ray, optical, and IR datasets will allow us to ascertain mass, age, and circumstellar disk fraction distributions for the entire young stellar population as a function of environment within the Carina Nebula. HAWK-I is uniquely suited to such a survey: it combines a wide, con- tiguous field, good spatial resolution, and very high sensitivity, making it possible to survey a good-sized region to a great depth, including densely-crowded clusters, in a reasonable amount of observing time. Demonstrating this would be an excellent use of SV, complementary to extremely deep, single-field extragalactic programmes, and the proposed survey would also be a valuable resource for studies of massive star formation.


Seifart et al.: Deep imaging in Chamaeleon I

Programme ID: 60.A-9284(L)
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Chamaeleon I is one of the nearest cradles of starformation to the sun, at a distance of 160�180 pc and an age of about 2 Myrs. Multiwavelength studies revealed far more than 100 stellar and a dozend sub- stellar members (Luhman 2004), most of them being concentrated in two distinged regions, Cha I north and south, separated by about 1 deg in Declination. Precedent infrared imaging campaigns where car- ried out with NTT/SOFI and VLT/ISAAC between 2000 and 2002. We propose to use the wide-field deep imaging capabilities of HAWK-I to add a new epoch to these observations in order to determine proper motions of the stellar and substellar members, and in conjunction with new radial velocity measurements - obtained with UVES (Joergens et al. 2003, 2006) - space motions and kinematics. HAWK-I is much more efficient for this purpose than ISAAC, since large spatial coverage is requested.


If you have any questions on the HAWK-I Science Verification, please contact Markus Kissler-Patig