July 27, 2001
The giant merger remnant galaxy NGC 1316 (Fornax A) is an ideal probe for studying the long-term effects of a past major merger on star cluster systems, given its spectroscopically derived merger age of ~3 Gyr which we reported in a recent paper. Here we present new ground-based, large-area optical and near-IR imaging of star clusters in NGC 1316, complemented with deep HST/WFPC2 imaging. We find that the optical-near-IR colours and luminosities of the brightest ~10 clusters in NGC 1316 are consistent with those of intermediate-age (2-3 Gyr) populations. Unlike `normal' giant ellipticals, the B-I colour distribution of clusters in NGC 1316 is not clearly bimodal. However, the luminosity functions (LFs) of the blue and red parts of the cluster colour distribution are different: The red cluster LF is well represented by a power law with index -1.2 +/- 0.3, extending to about 1.5 mag brighter (in B) than those of typical giant ellipticals. In contrast, the shape of the blue cluster LF is consistent with that of `normal' spiral and elliptical galaxies. We conclude that the star cluster system of NGC 1316 is a combination of a population of age ~3 Gyr having roughly solar metallicity and a population of old, metal-poor clusters which probably belonged to the pre-merger galaxies. After the 3 Gyr old, metal-rich clusters fade to an age of 10 Gyr, they will form a red `peak' in a bimodal cluster colour distribution. This `red peak' will have a colour consistent with that found in `normal, old' giant ellipticals of the same galaxy luminosity (taking age dimming into account). These features of the star cluster system of NGC 1316 are fully consistent with scenarios for forming `normal' giant elliptical galaxies through gas-rich mergers at look-back times $\ga$ 10 Gyr.
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October 13, 2000
We report on multi-object spectroscopy of 37 candidate star clusters around the giant early-type radio galaxy NGC 1316 (Fornax A), the brightest galaxy in the Fornax cluster. For the star clusters in this sample, we measure a mean radial velocity of 1698 +/- 46 km/s, a rotation velocity of 175 +/- 70 km/s, and a velocity dispersion of 227 +/- 33 km/s within a galactocentric radius of 24 kpc. Using the projected mass estimator and assuming isotropic orbits, the estimated total...
August 13, 2001
The giant early-type merger remnant galaxy NGC 1316 is an ideal probe for studying the long-term effects of a major merger on its globular cluster (GC) system, given its spectroscopically derived merger age of 3 Gyr which we reported in a recent paper. Here we report several pieces of photometric evidence showing that the second-generation GCs in NGC 1316 are at an evolutionary phase in between that of luminous GCs found in younger merger remnants such as (e.g.) NGC 7252 and ...
July 14, 2016
This paper presents Gemini-$gri'$ high quality photometry for cluster candidates in the field of NGC 1316 (Fornax A) as part of a study that also includes GMOS spectroscopy. A preliminary discussion of the photometric data indicates the presence of four stellar cluster populations with distinctive features in terms of age, chemical abundance and spatial distribution. Two of them seem to be the usually old (metal poor and metal rich) populations typically found in elliptical g...
August 4, 2004
The Advanced Camera for Surveys on board the Hubble Space Telescope has been used to obtain deep high-resolution images of the giant early-type galaxy NGC 1316 which is an obvious merger remnant. These observations supersede previous, shallower observations which revealed the presence of a population of metal-rich globular clusters of intermediate age (~ 3 Gyr). We detect a total of 1496 cluster candidates, almost 4 times as many as from the previous WFPC2 images. We confirm ...
March 8, 2012
NGC 1316 (Fornax A) is a prominent merger remnant in the outskirts of the Fornax cluster. The cluster system has not yet been studied in its entirety. We therefore present a wide-field study of the globular cluster system of NGC 1316, investigating its properties in relation to the global morphology of NGC 1316. We used the MOSAIC II camera at the 4-m Blanco telescope at CTIO in the filters Washington C and Harris R. We identify globular cluster candidates and study their col...
March 29, 2001
We have studied the Globular Cluster System of the merger galaxy NGC 1316 in Fornax, using CCD BVI photometry. A clear bimodality is not detected from the broadband colours. However, dividing the sample into red (presumably metal- rich) and blue (metal-poor) subpopulations at B-I=1.75, we find that they follow strikingly different angular distributions. The red clusters show a strong correlation with the galaxy elongation, but the blue ones are circularly distributed. No syst...
April 8, 2004
Recent observations of globular clusters (GCs) in intermediate-age (2-4 Gyr old), early-type merger remnants have provided the hitherto `missing link' between young merger remnants and `normal' elliptical galaxies in the form of a GC subsystem with colors and luminosities consistent with population synthesis model predictions for those ages and ~solar metallicity. Here we present new, deep observations of the GC system of the intermediate-age merger remnant NGC 1316, using th...
March 6, 2012
We study mass functions of globular clusters derived from HST/ACS images of the early-type merger remnant galaxy NGC 1316 which hosts a significant population of metal-rich globular clusters of intermediate age (~3 Gyr). For the old, metal-poor (`blue') clusters, the peak mass of the mass function M_p increases with internal half-mass density rho_h as (M_p proportional to rho_h^0.44) whereas it stays approximately constant with galactocentric distance R_gal. The mass function...
June 11, 2014
The merger remnant NGC 1316 (Fornax A) is one of the most important objects regarding the investigation of merger-related processes. We use kinematical data of globular clusters (GCs) and the diffuse stellar light to investigate the global structure of NGC 1316 and to constrain the dark matter content. We perform multi-object-spectroscopy with VLT/FORS2 and MXU. Out of 562 slits, we extract radial velocities for 177 GCs. Moreover, we measure radial velocities of the integrate...
September 4, 2017
The giant elliptical galaxy NGC 1316 is the brightest galaxy in the Fornax cluster, and displays a number of morphological features that might be interpreted as an intermediate age merger remanent ($\sim$3 Gyr). Based on the idea that globular clusters systems (GCS) constitute genuine tracers of the formation and evolution of their host galaxies, we conducted a spectroscopic study of approximately 40 globular clusters (GCs) candidates associated with this interesting galaxy. ...